in investigating the pressure to which the air in the lungs is exposed when employed in sounding certain reed instruments, and had found it for the clarionette equal to the pressure of the atmosphere, plus a column of water of 30 centimeters. In order to extend these inquiries to the human larynx, it was necessary to find a person having an opening in the trachea, and yet able to produce vocal sounds at will. After long search, Cagniard-Latour found such a man, who was for his purpose as precious as the subject with the permanent gastric fistula became for the well-known experiments of Dr. Beaumont. In the same year he made known his chronometric balance, designed to measure the dynamic effects of machines in motion.

Next appeared a memoir on the alcoholic fermentation, of which these were the principal results:

1st. The yeast of beer is made up of little globular bodies, apparently vegetable, and capable of reproduction in two different manners. These bodies seem to act upon a solution of sugar only when in a state of life, and he hence conceived it probable that it is by a vital process that they transform the sugar into carbonic acid and alcohol. This investigation was suggested by a question long before proposed as the subject of a prize by the French Academy of Sciences, in the seventh year of the Republic, viz. What are the characters which distinguish among animal and vegetable matters, those which serve as ferments and those which are subject to fermentation?

Čagniard-Latour now resumed his researches upon vibrating bodies, and succeeded in producing a sound by causing a glass rod to oscillate easily between two metallic columns. The peculiarity in the sound thus obtained was that the number of vibrations indicated by it corresponded only to one-half the synchronous number of simple oscillations of the rod, although the apparatus was arranged in such a manner that each movement backwards and forwards should produce two strokes of equal intensity, by the alternate blows upon the two columns. The experiments made with this instrument enabled him to give the theory of the produc tion of sounds by vibrating cords. During the same year (1840) he studied the production of grave tones, like those of the human voice, and made various researches to discover the mechanism of the human voice. In 1851 he laid before the Academy a memoir upon the moulinet à battemens, demonstrating some new acoustic phenomena. In two previous papers published in 1830 and 1831, upon the sounds produced by solid bodies turning with great velocity, he had shown certain facts relative to the musical tones produced by the friction of the axle of a wheel against its supports. Subsequently he conceived the idea that a solid of revolution, a cylinder for example, arranged so as to turn vertically around its axis upon two center-holes, night give rise to pulsating sounds (beatings), although moving with a feeble velocity, provided it received in the lower center-hole the friction of the revolving axis of a winch turning in an opposite direction to the cylinder. It was to the instru ments constructed according to these ideas that he gave the name of the moulinet à battemens.

We have also from Cagniard-Latour an investigation on the action of heat on different kinds of wood enclosed in hermetically sealed glass

tubes. Sir James Hall, in his experiments upon the saw-dust of pine wood and of horn in sealed gun-barrels, had observed that the mixture underwent fusion and was cemented into a sort of coal. Similar results were obtained by Latour with thick glass tubes.

These are not the only researches which we owe to this lamented physicist; in our previous letter we mentioned that while connected with the Government powder works in 1814, he made some useful improvements in that department, especially in the glazing of powder. We also spoke of his very light, portable, and efficient flour-mill, which consisted of a steel rasp moving vertically with an alternating motion between two fixed rasps, also of steel. During the severe winter of 1816, the streams being all frozen and the mills stopped, Cagniard-Latour was directed to have an immense number of these hand-mills constructed, and thus in a few days the public were saved from the fears of a famine. We have also seen the part which he took in the establishment of gas-lighting in Paris. He was besides the constructer of an aqueduct, a model of its kind, suspended between two rocks, and formed of a single span 200 metres in length. When we consider these varied achievements, we learn with surprise that it was only in 1851 that he became a member of the Academy of Sciences.

The aurora borealis and its theory.-The late brilliant auroras have called attention to De la Rive's theory, of which we have formerly spoken, and which is explained at length in his Traite d'Electricité. Great perturbations were observed along the telegraphic lines over the European continent, similar to those remarked some years since by Matteucci in Tuscany, and Highton in England. The most remarkable fact in these electrical disturbances is that they were produced by a continuous current, while those of a thunder storm are instantaneous, and only mark points upon the paper in Morse's apparatus; the aurora of the 29th August traced continuous lines of greater or less length. These effects lasted for several days after the aurora.*

It is fortunate that the aurora of the 29th was carefully studied by a man so competent as Coulvier-Gravier. This observer, who has studied the heavens for nearly 60 years, and has so much advanced the sciences of Cosmography and Meteorology, was found that night as usual at his post in the observatory which the government prepared for him twenty years since at the Luxembourg palace. The phenomenon was in all its splendor at 2h 45m A. M.; its extent included more than 100°, and M. Coulvier-Gravier declares that he had never seen it more beautiful during the long period of his observations.

The observations during the late auroras support the theory of De la Rive, which he has thus defined. The vapors constantly rising from the sea, and especially from the equatorial regions, carry with them to the higher regions of the air a great quantity of positive electricity, to which they serve as the vehicle, leaving the surface of the globe negatively electric. Borne to the poles by the currents which always prevail in the higher regions of the atmosphere, these vapors carry with them their electricity, and thus give to the whole atmosphere a positive electric condition, which diminishes from above downwards. This positive electricity tends unceasingly to combine with the negative electricity of the earth, See p. 92, this volume.

directly through the stratum of air, but more especially at the two poles, where the currents of vapor carried by winds converge and are condensed.

According to Mr. De la Rive the aurora of the 29th August was a natural consequence of the great drought which had prevailed over the continent. The dryness of the air bad prevented the positive electricity from neutralizing itself directly with the negative of the earth. From this accumulation of electricity there finally took place towards the polar regions a discharge much more intense and much more rapid than usual, which constituted the brilliant aurora in question. A fact which tends to show that the aurora is an electrical and not a magnetical phenomenon, is furnished by the ozonometrical observations made by Mr. Perigny, at Versailles. From the 28th of August to the 2d of September, he found the air to contain a quantity of ozone, relatively large, and more abundant by night than by day.

Human Remains in the Drift.-For the last twenty years it has been known that axes of flint, evidently wrought by human skill, were found in beds of the drift at Amiens, associated with the bones of extinct species of animals. This discovery, made by a learned antiquary, Mr. Boucher de Perther, had been regarded as doubtful, and it was supposed that sufficient precaution had not been observed in conducting the explorations. Recent discoveries made in a cavern at Brixham, near Torquay, in England, however, recalled attention to the observations of Mr. Perther, and Mr. Prestwich, with several other geologists, accordingly visited Amiens in order to make the excavations necessary to decide this important question. Every precaution was of course taken to prevent errors or deception, and Mr. Prestwich could find nothing at Abbeville, but at Amiens he was more fortunate; one of his companionз, Mr. Flower, in examining a bed of gravel at six meters from the surface, and evidently undisturbed, extracted with his own hands a fine axe, more than five inches long. After this Mr. Prestwich having been informed that a similar discovery had been made in 1737, at Haxne, in Suffolk, visited the place, and learned that some years since wrought flints were still found in abundance, although rare at present. He however succeeded in finding two axes, similar to those of Amiens, but of less perfect finish. An analogous fact has just been verified by French geologists, who have found these axes in Picardy, associated with remains of Elephas primogenius, Rhinoceros tichorhinus, Equus fossilus, and an extinct species of Bos. The conclusion from all these facts is that man was cotemporaneous with these several species of large animals now lost, and known to us only by their fossil remains.

Curare in the treatment of Tetanus.-This important question has elicited much discussion at the Academy, and many contradictions and differences of opinion. In 1850, Mr. Claude Bernard showed that the curare, or arrow poison, acts by paralyzing the system of motor nerves; following up this observation, an Italian physician, Villa, of Turin, made in 1854 a series of experiments, in the course of which he showed that curare exerts upon the nervous system an action so completely antagonistic to that of strychnine, that the two poisons may be neutralized by each other. Dr. Villa having been attached to the French hospitals during the late war, was induced to apply the curare in the treatment of three cases of trau

matic tetanus one of which recovered. It was the case of a soldier wounded by a ball in the right foot. The curare dissolved in water was applied to the wound, with the effect of diminishing the pain and suspending temporarily the tetanic spasms, which, however, returned. After fifteen days of this treatment the patient left the hospital completely cured. The experiments of Mr. Villa have been repeated in the hospitals of Paris; but as yet only a single case of cure has been reported out of several failures; the experiments, however, continue. According to a letter from Sir Benj. Brodie, of London, to the Academy of Sciences, the application of curare as a specific against tetanus, was unsuccessfully made upon horses at London in 1815, by Dr. Sewell, professor at the Veterinary College. Such are the principal facts in the question as far as yet made known.*

The new alloys of Platinum.-We recall the interesting researches of Messrs. Deville and Debray on this subject only to mention their industrial applications. Hitherto it had been supposed that the presence of iridium impaired the quality of platinum, but the labors of Deville and Debray have shown that on the contrary alloys of these two metals may be prepared which are greatly superior to pure platinum, presenting greater strength and rigidity, and resisting better both heat and acids. Thus the alloy containing 213 of iridium is highly malleable and scarcely attacked by aqua regia. As the quantity of iridium is less, the alloy becomes softer, and one containing 10 or 15 per cent. is peculiarly fitted for chemical vessels. These alloys are now largely wrought in Paris; retorts for the manufacturers of sulphuric acid have been made, having the strength and rigidity of rolled iron.

Messrs. Deville and Debray are at present making some trials at the French mint, for the Russian government, to determine the fitness of the new alloys for coinage. They have found that those containing 20, 10, 74 and 4 per cent of iridium, take the impression of the dies with great perfection. The same is true of the natural alloy, which is obtained by directly fusing crude platinum, and retains only the iridium and rhodium in combination with the platinum, the other metals having been removed by volatilization or oxydation. The platinum workers of Paris are now manufacturing and selling the new alloys, and, contrary to the wishes of the discoverers, are exacting higher prices than for pure platinum.

Rifled Cannon.-The invention of these guns appears to be due to a former captain of artillery, Mr. Tamisier, who was in 1842 charged with the course of instruction in musketry at Vincennes, where he applied himself with great assiduity to the study of various questions connected with his profession, with results which have contributed very much to the improvement of the system of musketry instruction in the army and in the arms of precision. After studying the effects of elongated projectiles in rifles and muskets, Mr. Tamisier was led to construct a rifled mortar, with cylindro conical shells. The duke of Montpensier, then colonel of artillery, at once saw the importance of this new project, and after causing many experiments to be made, ordered at his own expense, in 1847, the construction by Capt. Tamisier of elongated balls and shells. These however were not tried until 1850, from which time up to 1853, Mr.

See experiments on two new varieties of South American arrow poison by Drs. Haminond and Mitchell, Am. Jour. Med. Sci., July, 1859, (this Jour. [2], xxviii, 303).

Tamisier continued his experiments at Vincennes and at La Fère. The first experiments were made at Vincennes, on the 15th of July, 1850, when it was shown that rifled six-pounders with elongated projectiles, carried much farther and with greater exactness than ordinary guns of smooth bore. On the 14th August, 1851, Capt. Tamisier repeated his experiments at the polygon at Vincennes, before the President and the Minister of War. A six-pounder rifled with three grooves projected balls of five kilogrammes to a distance of 1500 meters with a charge of only 700 gramines of powder. The government then ordered further experiments to be made, which were conducted at La Fère, a fortified place in the Department of the Aisne, where greater secrecy could be secured than near Paris. The trials were there made by Col. Trenille and by Col. Virlet, now directors of the School of Artillery at Metz, and led to a complete solution of the problem, so that the army of Italy was able to bring into the field more than 200 rifled guns of a calibre of 84 millimeters, requiring for service and transport only two-thirds the men and horses hitherto necessary, and carrying balls of four kilogrammes 3500 meters with such precision that at this distance they would all fall in a rectangle of 80 meters in length by 40 meters in breadth.

Acclimatation. In our last letter we spoke of a number of Arabian camels, which the Society of Acclimatation had procured in Algeria, to be introduced into Brazil. We learn that they were safely landed there after a voyage of 28 days.

Photo-Chemical Researches: Persistent Activity of Light.-In this Journal for March, 1859. p. 257, we have described the beautiful experi ments of Niepce de St. Victor, upon the persistence of the effects of insolation. According to Mr. Laborde, the curious results obtained by Mr. Niepce are due not to radiation, but to a veritable emanation from the card-board, which has been impregnated with tartaric acid, and exposed to the sun-light. The principle subsequently evolved from this cardboard, which acts upon sensitive paper prepared with a silver salt, is, according to Mr. Laborde, no other than formic acid. This is well known to be a product of the oxydation of tartaric acid, especially when in contact with peroxyd of lead. He found that a concentrated solution of tartaric acid mixed with peroxyd of lead, and placed in a dark place, evolved vapors which reddened litmus and discolored prepared paper after a very short time. There is, then, in the case of insolated tartaric acid, an emanation and not a radiation; but Mr. Niepce obtained similar results with nitrate of uranium spread upon porcelain and insolated, in which case it is not easy to conceive of an emanation of vapor. However this may be, the facts announced by Mr. Niepce remain, and the only difference of opinion is as to their interpretation.

Maritime Canals.-Besides the canals proposed at Panama and Suez, the question of one between the Caspian and the Black Sea is now being discussed in Russia. The construction of such a canal was ordered by Peter the Great, after having been commenced a century before under the Sultan Selim II, upon the suggestion of his Grand Vizier, Mohammed Sokolli, who was for Turkey what Colbert was for France. The canal was commenced in 1569, and during two years there were employed upon it 5000 janissaries and 20,000 prisoners.