RICHARD A. PROCTOR. THE LOSS OF THE CAPTAIN. must be when weighed against the priceless lives of If I thought a sufficiently large proportion of your For God's sake let us try to realize what is so real to thousands of our fellow-creatures. We are inapt to sympathize with what is afar off; but let us not, therefore, suffer our fellow-men to perish. If the imagination is weak, let reason and generosity be strong. Year after year our shores are strewn with wrecks. Every gale which sweeps our coasts leaves on its track the dreadful traces of its fury. Do what we will the lives of men must be lost when the lives of stout ships are crushed out by the remorseless sea. But every soul in those wrecked ships has a claim on us for help. Every prayer of theirs and of those who witness their destruction is an appeal to us for sympathy. The tears that course down the face of pitying women as brave men that might be saved are borne away to death should soften our hearts to mercy. Yes, to mercy; for where it is in the power of men to save and they will not, they are as those that harden their hearts to slay. Let every reader of ours give but a little and our life. boat will be launched-let each give what he can, and there will be not one lifeboat but ten; and who shall say how many lives we shall have helped to save before ten years have passed away? Above all, let not those who can give but little be ashamed to send their help. Our lifeboat must have planks and keel, but if she have not nails also she will never be set afloat. Let us all give, and give quietly and give gladly, thanking those in our hearts who have shown us how we may help to save the brave men who for our sake "go down to the sea in ships." RICHARD A. PROCTOR. THE EARTH'S ROTATION AND THE TIDES. the tidal wave. [431] SIR,-From what I have seen it appears that May I be allowed to suggest that one simple feature I cannot claim the credit of originating the idea, for of the Royal George's boats, and was so effectual as to The contrivance I allude to is simply a triangular or HEREPATHITE. your columns, I have come to a conclusion that thermometrical readings carefully noted below the surface of our earth do indicate earthquakes." I am not prepared to say they will foretell them. My thermometer is 2ft. below the surface, in a common drain pipe, its variations (noted daily at 8 a.m.) agree with others miles apart, and in different geological strata : one for example, at the foot of Portsdown-hill, below the chalk, another 200ft. above in pure chalk: our thermometers differ, our variations 58 Earthquake at California. 40° 42° Colliery explosion and gale. 40° 59° ,, 56 Earthquake at Santorin. 37° 61° Earthquake in Greece. 60° I do not pretend to be a scientific man or a careful observer, but I think these things are curious. Any one can note for himself if a thermometer 2ft. below the ground does vary or not. As regards the sun act ing as a magnet or an electro-magnet, on our internal minerals,-are these minerals in our earth? are our earth and our atmosphere agreed in electricity? Is not one positive the other negative, showing a current of electricity? Where can this go to but the sun? C. J. R. [There is an interesting letter from the Rev. W. W. Woods, of Manila, in this week's Building News on the great earthquake there in 1863.-ED..] AURIC CHLORIDE. your correspondent signing himself "J. Pickles," and [434] SIR,-The solution of the first query sent by running, "What is the action of a red heat upon the following substances, placed so as to be out of contact with air ?" (Query No. 4938): [432] SIR, (Letter 427, p. 16.) The lamented Prof. [429] SIR,-With reference to the question of Herepath, in a communication to the Royal Society, "Beacon Lough," at p. 21 (in his reply to question 4773), gives the following formula for the preparation of it may be regarded as all but certain that the carth's herepathite:-"Dissolve 10 grains of disulphate of rotation is being continually retarded by the action of quinine in half a fluid ounce of alcohol, having 3 grains EXAMINATION QUERIES.-PICRIC ACID AND But the question is by no means so of benzoic acid dissolved in it also; adding 2 drachms simple as it looks, because though there is an appa: then, upon adding a few drops of spirituous solution of of water, and warming the whole to complete solution; rent transference of water in the tidal wave (I do not iodine, and placing in repose, prismatic crystals are refer to the apparent progress of the wave itself), yet the larger portion of the disturbance is merely a trans-produced." There is great difficulty in getting the ference of motion. Delannay's first investigation was crystals large enough to be serviceable for microfounded on a somewhat inexact basis, but Airy has re- polariscopy, and even if they be obtained they are not investigated the matter and finds a real cause of reto be depended upon for persistency. Thus their great tardation among the complex relations presented by advantages over Iceland sparare, so far as the amateur The whole matter is, however, far too microscopist is concerned, entirely neutralized. diflicult for discussion here; nor has it yet been inves- think "Vulpecula "has greatly overrated the difficulties tigated to the end. Indeed, the theory of tides itself attending the construction of a "Nicol polariscope." it in a most unsatisfactory state, the ordinary explana-Certainly it would not be easy for an amateur to conn in our books of geography and astronomy being struct a really high-class one, but the difficulties atatly opposed to the theoretical results of a dynamical tending the construction of a polariscope from Iceland spar would not nearly equal those attending herepathite. I would recommend "Vulpecula" to purchase from some P.S.-I cannot agree with "Gimel's" views about the optician the unmounted prisms, and to fit them himrotation of celestial bodies. If he had said that the the Nicol analyzer should go into the tube, although As I have before stated, it is not essential that moon rotates so slowly as she does because of the that is upon the whole its best position. I frequently earth's influence that would have been nearer the use mine above the eyepiece, and arranged in a cardtruth. Many thanks to him for his very kind expres-board contrivance, devised "in a hurry" to meet a sions regarding myself. been treated in your columns lately. The calculus is such "Oxonian [433] SIR,-In yours of 23rd Sept., p. 15, No. 411, I find under "Bicycle Riding," Mr. F. J. Walker says:"I should very much like to see 'C. J. R.'s' reasons for supposing his thermometrical readings have anything to do with earthquakes. Also in what way the sun acts as a magnet on the metallic mass in the interior of our globe." In our Bible the same word in the original which is used for "light" in Genesis is used in Job for electricity, and in Isaiah for fire; I infer, therefore, there is a decided connection between them. Again a flash of lightning, at one time gives light, at another sets fire to any object. We see the same in the electric spark. By a series of observations, which would be too tedious to write out and would fill too much space in Ferric bisulphide, Fe.S2, is reduced to the ferrous sulphide, Fes. Stannic sulphide, SuS, is changed into its stannous sulphide SnS. Flatinic sulphide, PtS2, loses sulphur and becomes platinous sulphide, PtS. Auric sulphide, AugS3, is converted into gold and sulphur. And arsenious sulphide, As2S3, volatilizes unchanged. The second query, No. 4939, "State exactly how you would separate from each other, and individually detect the following constituents of a solid substance given to you for analysis-Peroxide of mercury, soda, protoxide of copper, protoxide of iron, magnesia, sarily of several methods of procedure. Perhaps sulphuric acid, and hydrochloric acid," admits necespractically the best would be as follows: precipitate the two acids, the hydrocholoric acid by Dissolve in hot nitric acid, dilute with water, and argentic nitrate, and the sulphuric acid with nitrate of barium. Filter and neutralize with ammonia, add a little hydrochloric acid and pass in hydrosulphuric acid to excess. The mercuric and cupric sulphides dissolve out the cupric sulphide with potassic cyanide, will be precipitated; filter, wash the precipitates, and and the mercuric sulphide by a mixture of potassic hydrate and sulphide. The filtrate from the precipitated sulphides is to be rendered alkaline with ammonia, which precipitates the ferrous sulphide. Filter, boil well, evaporate to dryness, and iguite cautiously. Redissolve in water, precipitate with potassic carbonate the magnesia, and with tartaric acid the potass. Or ignite strongly and dissolve out the soda with water. solve in water as much as possible of the substance. Or he can adopt another method, as follows:-Disand precipitate with baric hydrate the sulphuric acid, and with silver sulphate the hydrochloric acid. Add to the filtered solution the residue dissolved in hydrochloric acid, and precipitate the mercuric, capric and ferrous sulphides as before; filter, boil well, and throw down the magnesia as magnesic phosphate by disodic phosphate. Evaporate to dryness and ignite, dissolving the sodic chloride in water; it will also contain the soda added. This second question can be varied in its reading, but if Mr. J. Pickles wishes simply an answer to the two Examination questions he sends, the above will do. "A. B." (No. 4928) had better use magnesic carbonate for neutralizing his gold chloride, and the best gold he can well obtain for making it is that sold by large chemists in books. Atomic "(No. 4892) had better use water and carbonie acid for his purpose, but I can hardly hope it would be of any real use to him. If he wishes to try, he had better half fill a pint bottle with water, acidulate with a little hydrochloric acid, and put in a very small piece of his chalk, and immediately pour in a bottle of soda-water, and cork tight up. Let it rest a week, and open for examination, This treatment would not affect any silicious-calcari shells or fossils. I do not quite see the tenability of "An Associate of the Royal School of Mines'" position (Letter 423), and that why on account of his inability to send a reliable test he should feel it necessary to forward a ralueless one. It is quite true "half a loaf is better than no bread," but that is no reason why a stone should be so. Neither do I exactly see the force of his assumption that, as I pointed out the unreliability and nselessness of the tests devised by himself and his cocorrespondent "Crow-Trees" for the purpose in question, I should be bound to give a better, as, though it may afford him a grain of comfort, I readily acknow. ledge my inability to devise any reliable method of detecting a few thousandths of a grain of pieric acid in beer that could be possibly of any value in the hands of a totally inexperienced person. I am not, therefore, at all surprised that your correspondent's "Crow-Trees" and An Associate of the Royal School of Mines" are not able to effect what would be a mere "miracle." Had the question been simply for a test to detect minute portions of picric acid, the matter would have rested on a very different basis. What did astonish me, though, was his sentence raxning "With respect to my answer to Young Photo,' I perhaps inferred too much in supposing he wished to convert his silver residues into metallic silver." If he will kindly refer to "Young Photo's " query (No. 4622), he will find that he expressly stipulated that he wished to convert his electro bath into the nitrate of silver. With reference to his concluding sentence, allow me to remind him of the saying "quot homines, tot sententiæ," or perhaps he may personally prefer "vitiis nemo sine nascitur," and as everything, even quotations, run best in triplets, finish with "Ex nihilo nihil fit." "A. T.," No. 4933, shall receive a full answer next week. URBAN. ON RESONANT MASSES OF AIR CONFINED [485] SIR,-I should be very glad if any of my A so-called resonant air-chamber was formerly the almost universal characteristic of stringed instruments, and according to Mr. Jones it is used in some form (which, by the way, he omitted to describe, to my great sorrow) in the American reed-organ. All the early harpsichords had an air-chamber; in other words, the case had a close bottom beneath the soundboard. This plan was also adopted for the horizontal grand piano, which was originally little more than a harpsichord having hammers which struck, instead of plectra which plucked, its strings; and all the earliest pianos in the upright form, which I have seen, had close backs; but as the manufacturers of pianofortes have long since ceased to make them into boxes containing a mass of air beneath their sound-boards, I suppose they find doing so does not increase the loudness or sensibly improve the quality of the sounds produced by their instruments. That the quantity, and especially the depth, of the mass of air between the belly and back of a violin may influence the timbre of its sounds seems very probable. In a former number of the ENGLISH MECHANIC, a violin of extraordinary depth is described; but I don't remember it had any advantages commensurate with the increase of the difficulty to "chin" it, to borrow its maker's expressive word. but it has not been my good fortune in the course of AN URBANE WORD TO "SUBURBAN." So far from Suburban" offending me, the kindly In conclusion, I feel bound to bear testimony to the greatly improved spirit in which our correspondence is at each other, at least we did not "agree to differ" now conducted. Formerly we were rather apt to snarl quite so amicably as we now do. Having myself being a great transgressor in this way, it is no more than just that I should be one of the very first to cry peccavi. THE HARMONIOUS BLACKSMITH. PIANOFORTE WIRE.-WHAT WEIGHTS IT [437] SIR,-Will some of my fellow readers oblige 1. The diameters, expressed in fractions of an inch, 3. The breaking weights of each size. I am aware the latter information can only be com municated approximately, for it must depend not only THE HARMONIOUS BLACKSMITH. CAUSE OF THE EARTH'S REVOLUTION. The effects of the included mass of air in drums is also an interesting subject. Query, would a drum of (say) 80in. diameter have a better quality of tone, or would its sounds be louder if it were made 6ft. long, instead of 2ft.? or would it not be equally loud if made like a tambourine-i. c., with its tympanum exposed to the air on both sides? An enormous drum or tambourine, about 7ft. diameter, made by Distin, was used at Alfred Mellon's promenade concerts, which, if I remember rightly, had but one tympanum. The quality of its sound was very fine and extremely The second says a body set in motion in vacuo will powerful, being heard distinctly when accompanied by go on for ever if there is no body to influence it the whole orchestra. This would seem to indicate that granted, but would not this body go on straight? would two parchment ends to the hoop are unnecessary. I it revolve? That is my question. He says the sun does am the more confirmed in this opinion by the fact influence it; if so, supposing the sun cansed the earth that patents for the improvement of drums have been to form an orbit, would not each revolution of the obtained in which it is proposed to remove the cylinder earth round the sun be smaller? how then can our (ordinarily employed to keep the drum-heads apart), earth have been going on for millions of years and we and substitute a light metal frame of stretchers: making have no signs of becoming nearer the sun? kettledrums on the same plan is also claimed. This subject may have been exhaustively treated, The third reasons so near the second I see no difference with him. I wish Mr. Proctor would speak. tion of meteors." As we do not know the composition -supposing a body set in motion in vacuo it would EXTRACTING THE CUBE ROOT. [489] SIR,-I enclose a very concise arrangement of the process for extracting the cube root. I shall be much indebted to any of your readers who will inform me where it is to be found. I have used it for upwards of twenty years, but have never met with it in any treatise on arithmetic. I have been told it is or was in use at the Royal Academy at Woolwich. As it contains some good points, I shall be glad to give a detailed explanation of it should it be thought desirable. THE INVENTION OF THE SCREW-PROPELLER. [440] SIR,-Bishop Heber, in his diary, states that when on his visit to the King of Oude he was shown a steamer, made by an Englishman, which was propelled the controversies respecting the inventor. If any of by a screw. I have never seen this passage quoted in your readers possesses the diary in question, perhaps he would kindly copy out the passage for us. I think it was at the King of Oude's the bishop saw it; but it possibly may have been at some other potentate's. If the date of his visit should prove to have been earlier than 1826, Josef Ressel (mentioned in letter 370) must yield the palm to this anonymous Englishman. SCREW POWER. B. A. 398. The calculus must be taught nowadays, or in the calculus. in the first φ matics, and does not touch on the mechanical idea SUGAR MILLS MANUFACTURE. [442] SIR,-Albeit that "Machinator" did some months ago sarcastically mis-correct me, still as no one seems to have accepted his challenge to write on readily since my observations of their working in the "Sugar Mills " I will begin the topic, and all the more And West Indies a few years since convinces me that there to which the inhabitants are subject. The district luminous body-I do not mean its sensible motion, light, blue will be the predominant colour. The in which he practises consists geologically of the such as the flicker of a candle, or the discharge of other colours of the spectrum must, to some extent, Carboniferous and New Red Sandstone or Cheshire a luminous matter from the surface of the sun-be associated with the blue. They are not absent sandstone systems. The inhabitants of the first I mean an intestine motion of the atoms or but deficient. We ought, in fact, to have them all, are engaged in mining and agricultural occupations, molecules of the luminous body. Follow a train but in diminishing proportions, from the violet to those of the latter in agriculture. Anomia, with of ether waves to their source, remembering the red. We have here presented a case to the goitre, is a very prevalent disease amongst those at the same time that the ether is matter, dense, imagination, and, assuming the undulatory theory to living on the Carboniferous system, whilst it is elastic, and capable of motions subject to and deter- be a reality, we have, I think, fairly reasoned out almost unknown among those living on the New Red mined by mechanical laws, What, then, do you way to the conclusion that were particles, small in Sandstone system, and consumption is also more expect to find as the source of a series of ether comparison to the size of the ether waves, sown in prevalent amongst the inhabitants of the former. waves? The scientific imagination demands as the our atmosphere, the light scattered by those particles As anemia is a condition in which there is a origin and cause of a series of ether waves a par- would be exactly such as we observe in our azure deficiency of the oxide of iron which the blood ticle of vibrating matter as definite as that which skies. When this light is analyzed, all the colours naturally contains, Dr. Moffat was led to make gives origin to a musical sound. Such a particle we of the spectrum are found; but they are found in an examination of the relative composition of the name an atom or a molecule. Turned into their the proportions indicated by our conclusion. Let wheat grown on the soil of Cheshire sandstone, equivalents of sensation, the different light-waves us now turn our attention to the light which passes carboniferous limestone, millstone grit, and a tran- produce different colours. Red, for example, is pro- unscattered among the particles. How must it be sition soil between Cheshire sandstone and the grit. duced by the largest waves, violet by the smallest, finally affected? By its successive collisions with i The result of the analysis shows that the wheat while green is produced by a wave of intermediate the particles the white light is more and more grown on the soil of the Cheshire sandstone con- length and amplitude. Separately, or mixed in robbed of its shorter waves; it therefore loses more tains the largest quantity of ash, and that there is various proportions, the solar waves yield all the than its due proportion of blue. The result may be a larger quantity of phosphoric acid in it than in colours observed in nature and employed in art. anticipated. The transmitted light, where short the soils of the carboniferous and millstone grit Collectively they give us the impression of white- distances are involved, will appear yellowish. But systems; also a much larger quantity of oxide of ness. Pure unsifted solar light is white, and if all as the sun sinks towards the horizon the atmospheric st iron than in either of them. He has calculated the wave constituents of such light be reduced in distances increase, and consequently the number of that each inhabitant on the Cheshire sandstone, the same proportion, the light, though diminished the scattering particles. They abstract in succession p if he consumes a pound of meat daily, takes in in intensity, will still be white. The whiteness of the violet, the indigo, the blue, and even disturb nearly five grains more per day of the sesqui-oxide Alpine snow with the sun shining upon it is barely the proportions of green. The transmitted ligin of iron than the inhabitant of the Carboniferous tolerable to the eye. The same snow under an under such circumstances must pass from yellow system, who seems therefore to be subject to great overcast firmament is still white. Such a firmament through orange to red. This also is exactly what liability to ano-mia in consequence of the deficiency of enfeebles the light by reflection, and when we lift we find in nature. Thus, while the reflected light of iron and phosphoric acid in the food he consumes. ourselves above a cloud field and see, from a proper gives us at noon the deep azure of the Alpine skies, It is not only in the wheat grown upon the Carboni-position, the sun shining on the clouds, they appear the transmitted light gives us at sunset the warm ferous system; that there is a deficiency in the dazzlingly white. Ordinary clouds divide the solar crimson of the Alpine snows. The phenomens quantity of oxide of iron, and the phosphates, says light impinging on them into two parts-a certainly occur as if our atmosphere were a medium Dr. Moffat, but also in the blood of the animals reflected part and a transmitted part, in each rendered slightly turbid by the mechanical susreared upon it; so that the inhabitants upon that of which the proportions of wave motion which pension of exceedingly small foreign particles system take in a minimum quantity of these con- produce the impression of whiteness are preserved. Professor Tyndall explained the formation fa stituents of the blood, compared with that taken in There exists indubitable evidence to show that "artifical skies," as shown by an experiment de by the inhabitants of the Cheshire sandstone. He the light of our firmament is reflected light. The scribed by M. Morren, of Marseilles, at the last ja states that sheep were liable to ancemia-n fact light of the firmament comes to us across the direc- meeting of the British Association. Sulphur and which he attributed to sheep-walks being upon tion of the solar rays, and even against the direction oxygen combine to form sulphurous acid gas. It is trap and limestone hills, in the soil of which there of the solar rays; and this lateral and opposing this choking gas that is smelt when a sulphur is but little, if any, iron. rush of wave motion can only be due to the rebound match is burnt in air. Two atoms of oxygen and of the waves from the air itself, or from something one of sulphur constitute the molecule of sulphurons suspended in the air. It is also evident that, unlike acid. Now, it has been recently shown in a greate the action of ordinary clouds, the solar light is not number of instances that waves of ether issuing reflected in the proportions which produce white. from a strong source, such as the sun or the The sky is blue, which indicates a deficiency on the electric light, are competent to shake asunder part of the larger waves. In accounting for the the atoms of gaseous molecules. Therefore, I colour of the sky, the first question suggested by say, sharply and definitely, that the com analogy would undoubtedly be, is not the air blue? ponents of the molecules of sulphurous acid The blueness of the air has, in fact, been given as a are shaken asunder by the ether waves. Enclosing solution of the blueness of the sky. But reason, the substance in a suitable vessel, placing it in a basing itself on observation, asks, in reply, how, if dark room, and sending through it a powerful beam the air be blue, can the light of sunrise and sunset, of light, we at first see nothing; the vessel contain. which travels through vast distances of air, being the gas is as empty as a vacuum. Soon, howyellow, orange, or even red? The passage of the ever, along the track of the beam a beautiful skywhite solar light through a blue medium could by blue colour is observed, which is due to the libe no possibility redden the light. The hypothesis of rated particles of sulphur. For a time the blac a blue air is therefore untenable. In fact, the grows more intense; it then becomes whitish; and agent, whatever it is, which sends us the light of from a whitish blue it passes to a more or less perthe sky, exercises in so doing a dichroitic action. feet white. If the action be continued long enough, The light reflected is blue, the light transmitted is we end by filling the tube with a dense cloud of orange or red. A marked distinction is thus ex- sulphur particles, which, by the application of hibited between the matter of the sky and that of proper means, may be rendered visible. Instead of an ordinary cloud, which latter exercises no such sulphurous acid we might choose from a dozen dichroitic action. By the force of imagination and other substances, and produce the same effect with reason combined we may penetrate this mystery any of them. In the case of some-probably in the also. The cloud takes no note of size on the part case of all-it is possible to preserve matter in the of the waves of ether, but reflects them all alike. firmamental form for 15 or 20 minutes under the It exercises no selective action. Now the cause of continual operation of the light. During these 15 this may be that the clond particles are so large in or 20 minutes the particles are constantly growing comparison with the size of the waves of ether as larger, without ever exceeding the size requisite to to reflect them all indifferently. But supposing the the production of the celestial blue. Now, when reflecting particles, instead of being very large, to two vessels are placed before you, each containing be very small in comparison with the size of the sky matter, it is possible to state with great dis waves; in this case, instead of the whole wave tinctness which vessel contains the largest par being fronted and in great part thrown back, a ticles. The eye is very sensitive to differences of small portion only is shivered off. The great mass light, when the organ, as here, is in comparative THE MECHANISM OF OPTICAL ACTION. of the wave passes over such a particle without re- darkness, and when the quantities of wave motions PROYE ROFESSOR TYNDALL, in his lecture, at flection. Scatter then a handful of such minute thrown against the retina are small. The larger Liverpool, on the Scientific Uses o the foreign particles in our atmosphere, and set imagi- particles declare themselves by the greater whiteImagination," described the mechanism of light, nation to watch their action upon the solar waves. ness of their scattered light. I permitted a beam of and showed how a knowledge of its characteristics Waves of all sizes impinge upon the particles, and light to act upon a certain vapour. In two minutes was arrived at by a proper use of the imagination you see at every collision a portion of the impinging the azure appeared, but at the end of 15 minutes it combined with reason. He said:-There is in the wave struck off by reflection. All the waves of the had not ceased to be azure. Here were particles human intellect a power of expansion which is spectrum, from the extreme red to the extreme which had been growing continually for 15 minutes brought into play by the simple brooding upon violet, are thus acted upon. But in what proportions and which at the end of that time still defied the facts. The legend of the spirit brooding over chaos will the waves be scattered? A clear picture will microscope-what must have been the size of these may have originated in a knowledge of this power. enable us to anticipate the experimental answer. particles at the beginning of their growth? Whst In the case now before us it has manifested itself Remembering that the red waves are to the blue notion can you form of the magnitude of such par by transplanting into space, for the purposes of light, much in the relation of billows to ripples, let us ticles ? As the distances of stellar space give us a modified form of the mechanism of sound. We consider whether those extremely small particles simply a bewildering sense of vastness, without know whereon the velocity of sound depends. When are competent to scatter all the waves in the same leaving any distinct impression on the mind, so the we lessen the density of a medium and preserve its proportion. If they be not-and a little reflection magnitudes with which we are here dealing impress elasticity constant we augment the velocity. When will make it clear to yon that they are not-the us with a bewildering sense of smallness. We are we heighten the elasticity and keep the density production of colour must be an incident of the dealing with infinitesimals, compared with which constant we also augment the velocity. A small scattering. Largeness is a thing of relation; the test objects of the microscope are literally im density, therefore, and a great elasticity are the two and the smaller the wave, the greater is the mense. From their perviousness to stellar light things necessary to rapid propagation. Light is relative size of any particle on which the and other considerations Sir John Herschel drew known to move with the astounding velocity of wave impinges, and the greater also the ratio some startling conclusions regarding the density 185,000 miles a second. How is such a velocity to of the reflected portion of the total wave. and weight of comets. You know these extra be obtained? By boldly diffusing in space a ordinary and mysterious bodies sometimes throw medium of the requisite tenuity and elasticity. ont tails 100,000,000 miles in length, and 50,00 This universal medium, this light-ether, as it is miles in diameter. The diameter of our earth i called, acts as a vehicle, not as an origin, of wave 8,000 miles. Both it and the sky, and a good por motion. It receives, but does not create. Whence tion of space beyond the sky, would certainly b does it derive the motion it conveys? For the most included in a sphere 10,000 miles across. Let us f part from luminous bodies. By this motion of a this sphere with cometary matter, and make it on Dr. Turnbull, of Liverpool, thinks there is a connection between the geological conditions of soils and the health and diseases of the inhabitants living on the soils. Consumption is less common in the inhabitants living on the Cheshire red sand. stone than in those living on the soils of the Carboniferous system. In a work on this disease, he directed attention to the inequalities in the distribution of this, the commonest of all diseases, and urged the importance of investigating the causes of these inequalities, with a view to their prevention. He also pointed out that in the town of Liverpool, which had been the most unhealthy, but which initiated sanitary improvements, the statistics furnished by the late Dr. Duncan showed that these improvements reduced, in a remarkable manner, the mortality from phthisis. An inquiry into the results of sanitary measures in 25 of the large towns of England, which was made under the direction of the health officer of the Privy Council, has since proved that drying the soil by main sewers produces its first and greatest improvement in the mortality of large towns by reducing the number of deaths from this disease. This led to the first inquiry which has yet been made into the effects of geological conditions of the soil on the health of the inhabitants. The three south-eastern counties of Surrey, Kent, and Sussex have been carefully examined by Dr. Buchanan, under the direction of Mr. Simon; and this inquiry has brought to light the important fact that damp. ness of soil is a powerful cause of consumption. Now, we have already made it clear to our minds SEPT. 30, 1870.] ENGLISH MECHANIC AND WORLD OF SCIENCE.-No. 288. An easy calculation informs us unit of measure. that to produce a comet's tail of the size just mentioned about 300,000 such measures would have to be emptied into space. Now suppose the whole of this stuff to be swept together and suitably compressed, what do you suppose its volume would be? Sir John Herschel would probably tell you that the whole mass might be carted away at a single effort by one of your dray-horses. In fact, I do not know that he would require more than a small fraction of a horse-power to remove the cometary dust. After this you will hardly regard as monstrous a notion I have sometimes entertained concerning the quantity of matter in our sky. Suppose a shell then to surround the earth at a height above the surface which would place it beyond the grosser matter that hangs in the lower regions of the airsay at the height of the Matterhorn or Mont Blanc. Outside this shell we have the deep blue firmament. Let the atmospheric space beyond the shell be swept clean, and let the sky-matter be properly I gathered up. What is its probable amount? have sometimes thought that a lady's portmanteau would contain it all. I have thought that even a gentleman's portmanteau-possibly his snuff-box And whether the actual -might take it in. sky be capable of this amount of condensation or not, I entertain no doubt that a sky quite as vast as ours, and as good in appearance, could be formed from a quantity of matter which might Small be held in the hollow of the hand. in as to quantity and direction. Have the diamond, THE EFFECTS OF CARBONIC ACID. T 31 hand, during the periods of low eccentricity the mass, the vastness in point of number of the particles of our sky may be inferred from the continuity of its light. It is not in broken patches, nor at scattered points that the heavenly azure is revealed. To the observer on the summit communication he explained that the observations competitors of the species." He also assured Mr. B. W. Richardson read a paper on some the meeting of the British Association, Dr. "New Physiological Researches on the Effects of Carbonic Acid," and in the course of an interesting he had made were new, in that they related to the direct action of carbonic acid on animal and vegetable fluids, and they were interesting equally to first demonstrated from a specimen the result of still have the azure overhead. Everywhere through of carbonic acid under pressure. The result was a the atmosphere these sky-particles are strewn, subjecting a vegetable alkaline infusion to the action They fill the Alpine valleys, spreading like a deli-thick fluid substance which resembled the fluid cate gauze in front of the slopes of pine. They which exudes as gum from some trees. When this sometimes so swathe the peaks with light as to fluid was gently dried it became a semi-solid subabolish their definition. This year I have seen the stance, which yielded elastic fibres, and somewhat Weisshorn thus dissolved in opalescent air. By resembled caoutchouc. This observation had led proper instruments the glare thrown from the sky; the author to study the effect of carbonic acid on particles against the retina may be quenched, and albumen, serum of blood, blood itself, bronchial sethen the mountain which it obliterated starts into cretion, and other organic fluids. When the serum sudden definition. Its extinction in front of a dark of blood was thus treated with the carbonic acid under pressure and gentle warmth, 26° F., the colmountain resembles exactly the withdrawal of a veil. It is the light, then, taking possession of the loidal part was separated; but when the blood with eye, and not the particles acting as opaque bodies, that interfere with the definition. By day this the fibrine removed from it was treated there was would seem to be one well adapted to favour rapid of Mont Blanc the blue is as uniform and coherent as if it formed the surface of the most close-grained solid. Mr. Glaisher will inform you that if our hypothetical shell were lifted to twice the height of Mont Blanc above the earth's surface, we should the zoologist and botanist as to the anatomist. He the last 60,000 years, in a period of small eccen able to exclude from vision all stars between the only nine occasions when the eccentricity was so fifth and the eleventh magnitude. It may be no direct separation, the blood corpuscles seeming When and held that carbonic acid in the venous blood was as essential to the process of respiration GEOLOGICAL CLIMATES AND ORGANIC particles which defy both the microscope and the therefore, about one-seventeenth more heat in De- T MECHANICAL STOKING. following paper was read by Mr. J. Smith, the meeting of the British Association, the terest to all users of steam-power:-Our reasons and apology for bringing under your notice the subject of Mechanical Stoking" are, first, the importance to the mechanical engineer of everything that relates to furnace management, and especially the importance of any improvement that will enable him to perform the labour of stoking by a machine that will more efficiently discharge the required duty than human labour can; secondly, the visit of your society to our town enables us to submit to the judgment of a competent tribunal the merits or defects of a system of mechanical stoking that we have applied largely in different parts of the country. Several writers on the subject have directed attention to the desirability of substituting mechanical for hand stoking, as the only means of securing economy, efficiency, and smokelessness. Bourne, in his work on "Recent Improvements in the Steam-Engine," published last year, says:—“In steam vessels it is most desirable that some proper species of firing apparatus should be employed, as sea, especially in hot climates, is very great; I the labour and difficulty of firing large furnaces at believe that a good smokeless furnace and a good self-feeding furnace will come together." Considering the acknowledged importance of the subject, it does seem remarkable that so little has been done in this direction. Of the different fire-feeding machines, as they have been called, that have been employed at different times, I think I am correct in stating that excepting the one I wish to bring under your notice, Juckes' Endless Chain Grate is the only one that has received any considerable amount of approval. But although the Juckes' grate does, under favourable circumstances, prove the superiority of mechanical over hand-stoking, yet it does not, I think, sufficiently meet the engineering requirements of the present time; it has one serious defect-it is only applicable to externally-fired boilers, and is very cumbrous. A HE following is the substance of a paper read by Mr. S. A. Varley, A.I.C.E., before the Mathematical and Physical Science Section of the Bristol Association:- Lightning protectors were very generally used in the early days of telegraphy, but subsequently they were practically abandoned, as the protectors adopted only occasionally saved the coils, sufficient electricity passing through the coils when the wires were struck by lightning to mechanical stoker, to be successful, must preserve destroy them, notwithstanding that the greater in close proximity to one another. These are DR. G. W. CHILD read a paper on "Protoplasm and the Germ Theory," at the recent meeting of the British Association, of which we abstract the following: Protoplasm, as a rule, is a more or less viscous fluid, consisting mainly of four elements-oxygen, hydrogen, carbon, and nitrogen, such as constitute the living portion of every organism, animal or vegetable. We are unable by any process to discriminate between the protoplasm of the lowest plant and that of the highest animal; but as a matter of fact the protoplasm of one kind of organism so far differs from another as to conform to peculiarities of type. The earliest discoverable state of every organism was that of a simple minute mass of protoplasm, and beyond this stage many organisms never progress. Vegetable organisins are capable of assimilating to their protoplasm certain inorganic compounds, but the animal world has to find its nutriment ready made in the vegetable kingdom. After an examination of the various germ theories which have been put forward, it appears to Dr. Child that Abiogenesis in some form of another is a necessary consequence of certain other theories which are gaining ground at the present moment. It is hardly conceivable that we could theoretically hold that the original simple forms. from which the whole animal and vegetable world has been developed, have sprung into existence out of the regular order of the evolution of the universe. What is called the germ theory of disease throw an interesting light on the question. Zymotic dis eases are now generally believed to result from the multiplication and reproduction of germs in the blood of the man or animal affected. The matte to be accounted for is how the germ diseases appear, disappear, and afterwards again crop up in the same district and at great intervals of time. If the old theories are to be maintained in their entiret as to the fixity of species, every one of thes diseases must have existed somewhere from the beginning-a view hardly credible, but which is held nevertheless. Mr. J. Samuelson gave an account of the contre versy on Spontaneous Generation, and of some recent experiments. Referring to the theological bearing of the subject, which he believed to be overrated, inasmuch as it could make but little differ ence "whether the first appearance of the lowest type of animal and plant life is due to the direct action of the physical forces on matter which has once been organized, and is undergoing decompost tion, or to the same forces, or some modification of them acting in the first instance in or upon almost inconceivably minute pre-existing germs, the author expressed his opinion, resulting from experi ments and observations which extended over a long series of years, that those who prefer to adopt the theory of the creation of living forms only fre germs already in existence would eventually find their view to be correct. From recent experimenta Dr. Bastian believes that he has not only been ab! to create "protoplasm" by the combination of inorganic materials, as was hinted possible some years since by Professor Huxley, but that under his hands there have been spontaneously produced from inorganic materials, combined in a manner circumstantially described by him, truly "organized plants and small ciliated infusoria." Mr. Samuels criticised the terms in which Dr. Bastian had described the results of his experiments, characters ing them as vague and giving instances of this vagueness. He showed how some of them were absolutely adverse to Dr. Bastian's hypothesis; and described at length a number of experiments of his own made in June, July, and August last, comparing them with notes of a series of experiments tried by him in 1863, which left little doubt on his mind that the plant-types (mildew or mould), believed by Dr. Bastian to have been spontaneously produced in fusions, really spring from atmospheric germs, which, in some instances, become developed in the open air upon bare rocks and stones, but which the author showed to be present in rain-water fallen from the clouds, and in distilled water exposed to the air. The result of his experiments may be thas briefly epitomised: In 1863 he found the same plant types-various stages of mildew-in infusions of orange-juice, cabbage-juice, and pure distilled water exposed to the air; and during the past summer he again found the identical types in infusions of orange-juice, and in water caught in a shower types in the atmosphere. rain. At both periods, too, he found lowly animal He concluded as follows! Here I leave to the judgment of men of scient the results of my experiments, which any boy pos sessed of a microscope may repeat as effectually I have performed them. And if the believers |