the washings, should be a large pan, with a small round hole, about two inches from the inside bottom, which, till wanted, can be plugged up with a wooden peg. Into the solution throw a red-hot plate of copper, about the sixteenth of an inch thick, and at least half the size of the bottom of the pan; let it remain undisturbed for two days, at the end of which, drop two or three grains of common salt into the liquid; and if there is no appearance of cloudiness in the water they pass through, the silver is all precipitated. The water must then be drawn off at the little hole, giving the opposite side of the pan a gentle elevation to clear off as much of the water as possible; then plug up the hole again, fill the pan with clean water, and wash the silver off the plate of copper; removing which, rub the precipitate well between your hands in the water, to separate it from the acid, which may still cling to it; leave it to settle, which it will soon do; then pour off the water, and proceed as with the gold precipitate. The copper may then be obtained by the introduction of an iron-plate; but from the smaliness of its value, I have never been tempted so to do, except for the sake of the experiment.

The information given by your correspondent "Rose Colin," though strictly true, is not, I imagine, that which Niloe Esor seeks for. The mode I have pointed out has, I believe, been in use for centuries; but that there may be a better, or that there may be an improvement on this, I have little doubt; and I hope that those acquainted with either, will promote the cause of Science, by giving to its votaries all the advantages in their power through the same medium. I a, Gentlemen,

Your obedient servant,
G. STACEY.

No. 44.-TEMPERING IRON. GENTLEMEN ;-In reply to the query of your correspondent Z. Y., as to the inequality of the temper of iron, I beg to say, that the mode he has adopted of making new iron from old scraps, sunk in a charcoal finery, is quite at variance with the possibility of obtaining his ob`ject of procuring soft or regular iron.

Let him select good gray pig-iron, equal and regular in quality, and refine it; then work it under the hammer into a bloom or billet, and if proper care be taken, it will give him a regular good and soft iron, fit for most

purposes to which charcoal iron is applicable; if, however, it is wanted for some very particular purpose, where any admixture of tough with bright iron would be objectionable, let him stamp his charcoal lump under the hammer to half an inch in thickness, and immediately emerge it into a bosh or cistern of cold water; and afterwards ribble, ́or break it under the hammer cold. When broken with a sledge hammer into small pieces, the bright and tongh may easily be selected, and worked separate into blooms, and rolled. This will give your correspondent all he wishes.

No. 46.-FLAVOUR OF BRANDY." GENTLEMEN ;-Iu answer to the inquiry of your correspondent in your 48th Number, as to what is used to give the flavour to brandy, if he means the best brandy of France, which is Cogniac brandy, I must tell him that no artificial flavour is requisite, as the brandy has all the delicate, pure, delicious flavour on coming from the still. As a proof of this, I would recommend him to taste it. in this state, which he may do at any of the principal importers of brandy, where he will find it with no other colouring matter but what is extracted from the wood of the cask, and in which state it is drunk in Paris, and in other parts of France. John Bull, however, must have his humour, and therefore it is coloured for him with nothing worse than burnt sugar; but if the inquirer wishes to know what is used to flavour that abominable compound called British brandy, "I could a tale unfold," but that I have a high respect for certain individuals, called distillers, chemists, and others. whem such an exposure might injure; but, as Hamlet says,

"They do but jest, poison in jest;
No offence i' the world."

I am, gentlemon,
Your obedient servant,
BIBO.

INQUIRIES.

No. 53.-CLEANING MARBLE. How can the polish of marble tables, when water, tea, &c. has been spilt on them, be restored?

No. 55.-COAL-MINE QUERY. Cadoxton, Juxta Neath, GENTLEMEN ;-I beg leave, through the medium of your valuable work, to propose the following question, not doubting but its discussion will develop much useful information to many persons interested in coal properties.

There shall be two veins of coal, one nine feet thick, and the other four feet thick, whose local situations are exactly similar, both having good roofs or tops, each vein lying under twenty acres of land. I require to know what quantity of coal can be worked from each separate vein, and which of the two veins can be worked with the greatest profit, both to the lessor and the lessee, both paying the same royalty, and admitting each cubic yard to weigh 100 lbs.

A YOUNG COLLIER.

NEW PATENTS.

To William Harrington, of Crosshaven, in the county of Cork, esquire, for his improved raft for transporting timber.15th June-6 months.

To Charles Chubb, of Portsen, Hampshire, ironmonger, for his improvements in the construction of locks. 15th June -2 months.

To Benjamin Ager Day, of Birmingham, Warwickshire, fire-screen maker, for certain improvements in the manufacturing of drawer, door, and lock knobs, and knobs of every description.-15th' June-2 months.

To John M'Curdy, of New York,' United States of America, but now of Snow-hill, London, esquire, who, in consequence of a communication made to him by a certain foreigner residing abroad, is in possession of an improved method of generating steam.-15th June -6 months.

To Philip Taylor, of the City-road, Middlesex, engineer, for certain improvements in apparatus for producing gas from various substances.-15th June -6 months.

TO CORRESPONDENTS.

T. M. B.-W. G.-J. E.-and P. Y. on the London Mechanic's Institution, have been received; but we must defer the subject for a week. We shall only say at present that we have "insinuated"

nothing that we are not fully prepared to substantiate when the proper occasion: arrives.

We beg to refer Quivox, who wishes to know which of the Committee of Managers go out of office in September next, to the 72nd of the Rules and Orders, where he will find it provided that "The thirty committee-men shall also be elected for one year, and no longer, with the exception of those for the first year, of whom the last fifteen on the list shall go out of office on the first Tuesday of September, 1824, and be replaced by fifteen new committeemen to be then elected for the year ensuing." The last fifteen on the list are, of course, the fifteen who had the smallest number of votes, a statement of which will be found in our 17th Number, page 264.

T. G.'s paper has been forwarded as directed, not that we pronounce it " unworthy of insertion," but that we may abridge, as far as possible, the controversy to which it would lead.

T. M. B. will accept our best thanks for the sample of the instrument which he has so obligingly transmitted to us. It shall be left as directed, as soon as a drawing of it is made.

Communications received from D. to Quodlibet-Troublesome Tony - Nagthorn Copcake-The Corn-flour and Bread Company-W. H. D.-Scribotinto

-A Constant Reader-A Seaman-G. Thurnell North Star (whose duplicate of the same communication never came to hand)-E.-Bismuth-W. D.-PhiloLiverpool-Dr. Gilchrist-R. Cartwright A. B.-Mary-Domine-John Square -F.-Q. in the Corner-Johnson-Semiquaver-Dr. Smith-Preceptor-Previous Question.

Descriptive History of the SteamEngine, by ROBERT STUART, Esq. Civil Engineer. 1 vol. 8vo., Illus-. trated by Engravings of Fortyseven Engines. Price 8s.

We have much pleasure in bring ing under the notice of our readers the volume before us. It is at once the best and the cheapest account of the steam-engine that has yet appeared. Hitherto the facts of its history have lain so widely scattered, or when partially collected, have been retailed at so great an expense, that they have remained quite beyond the reach of those classes who, from being engaged in the construction of machinery, and in directing its operations when applied to manufactures, have naturally a greater interest in a knowledge of such facts, and by knowing them must be more likely to introduce and promote new improvements than any other body of men whatever.

Mr. Stuart remarks, with great truth, that all that has been done by merely learned men, in the application of steam as a moving power, is of no practical "mark or likelihood." Twenty years ago, Hornblower observed that "the most vulgar stoker may turn up his nose at the acutest mathematician in the world, for (in the action and construction of steamengines) there are cases in which the higher powers of the human mind must bend to mere mechanical instinet," and the observation applies with greater force now than it did then. We know not, therefore, how the remark has originated, or what "philosopher" first claimed, for theoretic men, any part of the honour of being instrumental, even indirectly, in the perfecting of the steam-engine; or who gave currency to the phrase of its "invention being one of the noblest gifts that Science ever made to mankind." The fact is, that science, or scientific men, never had any thing to do in the matter. It was a toy in the hands of all the phi losophers who preceded Savery, and it again must become a toy before the speculations of Bossut, the ablest and latent of the philosophers who have

written on the subject, can be made to bear upon it. Indeed there is no machine or mechanism in which the little that theorists have done, is more useless. The honour of bringing it to its present state of perfection, therefore, belongs to a different and more useful class. It arose, was improved, and perfected by working mechanics, and by them only; for tradition has preserved to us, the fact of Savery having begun life as a working miner;-Newcomen was a blacksmith, and his partner, Cawley, was a glazier;-Don Ricardo (Mr. Richard) Trevithick, was also an operative mechanic;-and so was the illustrious Watt, when he began and after he had made his grand improvements."

Mr. Stuart commences his history with an account of Hero, of Alexandria's engine, which is nearly similar to that given of it in our 25th, 26th, and 27th Numbers. "No other notice," he says, "of steam as a first mover occurs in the works of ancient authors, nor in modern writers, until about the year 1563." So it has been customary to state; but we can mention one modern instance, at least of a date more than five hundred years older, where it is distinctly recorded to have been applied to machinery. In Malmesbury's History we meet, under the date of 1002, with the following paragraph: "In the church of Rheims are still extant, as proofs of the knowledge of Gerbert, a public professor in the schools, a clock constructed upon mechanical principles, and an hydraulic organ, in which the air escaping in a surprising manner, by the force of heated water, fills the cavity of the instrument, and the brazen pipes emit modulated tones, through the multifarious apertures.' This we incline to think was the earliest modern application of steam; and we are rather surprised that it should have been so long overlooked.

دو

In 1563, one Mathesius hinted at the possibility of constructing an apparatus similar in its operation and properties to those of the modern steam-engine. About thirty years after that period, a Whirling Oelipile

was described in a book printed at Leipsig. It consisted of a globe with two necks, or outlets on opposite sides; a small quantity of water was introduced into it, and rarefied into steam by a fire made under it; the vapour issued then at the two necks, and by its reaction a continuous motion was generated.

In 1624, Solomon de Caus, a French engineer, described an engine acting by the elasticity of steam; but the first person who in modern times applied it on any scale, to a useful practical purpose, was Giovanni Branca, who resided at Rome in the beginning of the seventeenth century. A description of his engine (which was only an improved Oelipile) from the pen of Mr. Partington, has already been given in our 9th Number. Mr. Stuart adds, with truth, however, that to the merit of a first idea, assigned to him by Mr. Partington, Branca has no claim.

The elasticity of the vapour of water, which had now become familiar to water-work artists, was applied by them in a variety of ways to their favourite problem of raising water above its level in jets and fountains.

Mr. Stuart describes two of these Air Engines, as they were called, but very prudently, "without vouching for the great effects " said to have been produced by them.

Bishop Wilkins, in his Mathematical Magic, 1648, speaks of the Oelipiles as if in his time, and in England it had been extensively applied to useful purposes. "These are frequently used," he says, "for exciting and contracting of heat in the melting of glasses or metals.* They may also be contrived for sundry other pleasant uses; as for moving the sails in a chimney corner; the motion of which sails may be applied to the turning of a spit, or the like."

We come next to the pretensions of the Marquis of Worcester, who, of "all those whose names are associated with the history of the steam

* An authority, by-the-bye, in favour of our Goldsmith's Apprentice Steam-Soldering Machine.-See p. 273, Vol, II.

Since the performances of Hero, De Caus, and Branca have been brought to light, there can now be no doubt that the claims of the Marquis have been overrated; but not certainly to the extent represented by Mr. Stewart, whose acuteness on the subject is more to be admired than his liberality. Intending in an early Number to enter upon a full review of the whole of the Marquis's Century of Inventions, we shall defer till then the farther remarks we have to make on this part of Mr. Stuart's volume...

The author next describes the successive applications of steam, attempted by Sir Samuel Morland (1682), Papin, Amonton, and Savery, to all of whom, particularly the last, full justice is done.

"In his address and explanations, Savery proceeds with all the candour and earnestness of a man, conscious of having made a discovery of immense importance to mankind; and there is no greater instance of so open and candid an appeal to experiment, and an examination of the actual performance of an engine as a test of its merit in the history of mechanical inventions.

*

"This engine Savery applied for raising water for palaces, gentlemen's seats, draining fens, and supplying houses with water in general, and pumping water from ships; and he erected many of them in different parts of England. The power of his engine he limited only by the strength of the pipes and vessels; for (he says) I will raise you water 500 or 1,000 feet high, could you find us a way to procure strength enough for such an immense weight as a pillar of water that height."

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6

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"The advantage derived from the use of Savery's engine, as a substitute for manual labour, was counterbalanced in public opinion by the great risk of acoident from an explosion of the boiler;