steam-ship starting from Valentia, at the western side of Ireland. * practicability of steam will be established at

once.

The

Its speed and its certainty will induce interests, enough for its maintenance, to a greater or less extent, to support it. All correspondence will be conveyed by it; all mercantile travel, and some goods, Most passengers may be shy of it for a timemany for a long time (as some are of railroads still); accidents will happen, of course: still the scheme will go on to maturity. Of its influence on the other and far greater interests than yet alluded to, we cannot now speak. This is a theme not to be hastily treated. It is one, too, which may be deferred awhile. All eyes now are turned on the" commencement of the end." We may yet discuss, with improved data, the end of such a beginning.

NOTES AND NOTICES.

A Claimant to Dr. Arnott's Stove.--Sir,-Having read your pithy observations on Dr. Arnott's Thermometer Stove, &c., and his disinclination to take out a patent, inasmuch as he desires it to be widely known that the whole world may participate in the advantages it offers, allow me to observe, that Dr. Arnott ought to be just before is generous, for be it known to the Doctor that I hold a patent for burning combustible bodies for heating retorts in airtight chambers, kilns, ovens, &c. &c., admitting air by the ash pit to keep up any required or given heat; this being the principle of Dr. Arnott's Stove, I am surprised at his presuming to assume an invention not his own. My patent was taken out in the spring of 1833, and if the original drawings and specifications of this patent are of any service in your valuable work, you can have the loan of them at any time. By inserting this you will correct a misrepresentation, and do justice to an individual who wishes for nothing more than fair play. I am, Mr. Editor, your constant reader, J. I.Kennington-lane, March 15, 1838.

[We shall be obliged to J. I. for an inspection of his specification and drawing.-En. M. M.]

Dr. Franklin's Printing Press.-A lecture on self-education, was last week delivered at the London Mechanics' Institution, by Mr. Thatcher, of Boston, U. S., in the course of which, as might be supposed. allusions were made to that eminent countryman of the lecturer's, who may be called the great modern realization and model, practical and personal, of the philosophy of "making the most and best of one's self." After the lecture, we learned from Mr. Thatcher, that his researches after traces of Franklin's doing's in London have brought to light a relic, which few of our readers have either heard of or seen. The relic we refer to is the identical press which Franklin worked when with Mr. Watts, of Lincoln's Inn Fields. It is now the property of a member of the craft, and may be seen at Mr. Harrild's, Distaff-lane, Friday-street, who has also a complete, accurate, and well-authenticated pedigree of this precious machine. The tradition is still preserved among the trade, that when Franklin was here again in 1768, as the agent

of Massachusetts, he visited his old master, who still continued the business at the same place, sought out the press, which was still doing duty too, called the workmen together, and gave them, over a good noggin of porter, an account of the article, and a few words of comment in "poor Richard's" usual manner, which made a great impression. It is no longer used; but, though clumsy and rough, does not differ so much from common presses as might be supposed.-it being now 110 years since the philosopher pulled at it himself. We may add, as a proper postscript to this reminiscence, Mr. Thatcher's statement, that a "composingstick" of Franklin's was, within a year or two, sold by auction. It was authenticated clearly, and brought a high price.-Athenæum.

Steam Navigation in India.-The use of steamvessels has been found by experience so well adapted to the navigation of the rivers of Hindostan, that the supply is, for the present at least, greatly inadequate to the demand. On a recent occasion, when the company announced the intended dispatch of a steamer up the Hoogly, the competition among the merchants for freighting her was so great, that it was seriously proposed to determine precedence by lottery, it being evident that only a small proportion could be accommodated! Strong representations have been sent home of the necessity for immediately placing a greatly-increased number of steamers on this service, and the greatest anxiety is evinced for the accomplishment of the object. The company have at length given orders that the experiment should be tried of building a steam-ship at Bombay, the expense of which, from the cheapness of labour and materials, is expected to be much less than that of a similar vessel built in England. Her machinery will be made by artificers sent for the purpose from home, and she is directed to be made on the model of the Berenice, who has proved herself, by the voyage out, to be one of the best steamers afloat.

"Many a little makes a mickle".--So important is the manufacture of that apparently insignificant article, the pin, that in some years, pins to the value of £20,000, or (at least) three hundred million in number, have been sent to the metropolis, from Gloucester alone, within the twelvemonth! Gloucestershire is still the chief seat of the trade, the largest pin factory in the world being that of Messrs. Tayler, andCo., near Strous, where almost the whole of the requisite operations are performed by patent machinery.

India Rubber in the Army.-Caoutchouc is being daily applied to more and more useful purposes, abroad as well as at home. In the East Indies it has been put in requisition as a material, in lieu of leather, for the soldiers' belts and other accoutrements,an use for which itwould seem particularlywell adapted, as the article is to be had in abundance in India, it is probable that it will be found as preferable on the score of economy as in other, and even more essential respects.

Our engraver, Mr. W. C.Walker, has a vacancy for an apprentice. Cards of Address may be obtained from our publisher.

Mechanics' Magazine, Complete sets.-The proprietor of the Mechanics' Magazine has now effected the repurchase of the earlier portions of the stock of this journal from the parties who were possessed of the same in the right of his first publishers; and he is now able to supply several complete sets of the work. Price, twenty-seven volumes, half-cloth, 11 78.

MESSRS. HERAPATH AND COX'S NEW

PROCESS OF TANNING.

We have now the pleasure of laying before our readers, the first complete and authentic account yet published of this singularly valuable improvement in the art of tanning. Like most great inventions, it is of a very simple description -so simple, that, as usual, the wonder with most people will be, "how it should not have been found out long ago!" No trick of chemical magic is this-producing by some newly found out substance, or newly contrived combination of substances, a rapidity of transformation from the raw to the manufactured state, and an excellence of quality in the manufactured article, unheard of-unwitnessed before. It is simply a more judicious method of manipulation, by means of which the natural affinities of the tannin and gelatine for each other, are brought more quickly, fully and uninterruptedly into play, than by any of the processes heretofore in use. It is withal a method, the machinery requisite for which, is extremely cheap, easy of construction, and capable of universal application-to old tan pits as well as new. The general results are, that the hides and skins are converted into leather in one fourth of the time ordinarily required—that the tanner canof course derive from the sameamount of capital embarked in his business four times his former profit, or a like profit from one-fourth the capital-that the leather in point of resistance to moisture, (the grand criterion) is better than the best leathers hitherto known in the market, in the proportion, of at least ten to one-and that the weight of leather produced from any given weight of hides or skins is so much greater than usual (owing to there being less waste of the constituent elements, tannin and gelatine)-that the increase is of itself nearly sufficient to defray all the cost of the new process.

We would willingly dwell on the philosophy of the system by which such immense practical benefits have been realized-for it is, after all, to philosophy alone, or more properly speaking, to theory applied to practice, that we are indebted for this new process, which leaves all other processes so far behind it; but this we leave to Mr. Herapath himself (Mr. William He

rapath) who in his reply to Mr. Chaplin, inserted in another part of this day's Magazine, has accounted most clearly and satisfactorily for the great superiority of the new method over all others.

After the butts have undergone the usual preparatory processes, such as unhairing, rounding, fleshing, and graining, the patentees take as many as a pit will conveniently hold, the number varying according to the size of the pit, and attach them to one another by means of ligatures of strong twine or some other suitable material, either endwise or sidewise, taking care in the former case to join the hides butt to butt and shoulder to shoulder, and in the latter to join the butt side of each hide to the shoulder side of that next to it, so that the band formed may be as nearly straight and even as the shape of the butts will allow. They then connect the said band of butts with a system of rollers such as represented in figures, 1 and 2. Figure 1 as a front view with the side of the tan-pit removed for the sake of greater clearness, and fig. 2 a transverse section of the saine through the line A B of fig. 1. DD is a roller of wood supported by standards F F, which roller stretches across the top of the pit containing the tanning liquid. To one end of the axis of this roller there is affixed a cog wheel G, into which the pinion H on the shaft of the speed I is geared, which pinion is connected by a drum and strap in the usual way with a steamengine or other moving power. The standards F F support also at top two weighted levers LL, from which levers there is suspended a second roller E of smaller dimensions than D; by adjusting the weights on which levers according to the degree of pressure required, the roller E is made to press with more or less force on the under roller D, and to derive a rotary motion therefrom. The patentees state, that they find the proportion of ten to six, a convenient one between the two rollers, but that they do not confine themselves to that or any other rate of proportion. One end of the band of butts being brought over the under roller D, is fastened to the last of the butts, at the other end of the series, by ligatures in like manner as before directed, so as to form of the whole one endless band or belt. A

rotary motion being now communicated to the under roller D from the cog wheel and pinion G and H, the endless band of butts is made to revolve, and as each butt rises from the pit, and passes between the rollers D and E the partially or wholly exhausted liquor is pressed or squeezed out of it by the weighted roller, so that it descends again into the pit with its pores open for the reception of a fresh supply of tanning liquor. A boy attends to the endless band as it emerges from the pit (as shewn in fig 2,) to lay each butt smooth and even upon the under roller D; and it is found in practice that one boy can readily attend to two adjoining pits and pairs of rollers at a time. The pits the patentees have hitherto used are of the ordinary size and form, but they recommend that they should be made at bottom of a semi-cylindrical form, to allow of the endless band of butts turning round with greater ease.

MESSRS. HERAPATH AND COX'S NEW TANNING PROCESS-REPLY OF MR. HERAPATH TO MR. CHAPLIN.

Sir, I assure Mr. Chaplin (p. 353) that I have no wish to establish my patent upon the ruin or injury of any other. I am so frequently appealed to in cases of manufactural difficulties, and have seen such vast sums thrown away from a want of chemical first principles, that I am sometimes induced to give an opinion before it is asked; for doing so in this instance, I have to apologize, as Mr. Chaplin must be the best judge of his own affairs, and my only anxiety will be to explain those parts of my communication which have been thought inconsistent.

A solution for tanning upon entering the pores of the skin, is quickly deprived of its tanning and extractive matter, but the exhausted fluid remains within the tubes of a wet hide for weeks or months, being only slowly removed by the principle of exosmosis, or partially so by the operation of "handling." The desideratum of tanners has long been to find a cheap and quick method of getting rid of this exhausted ooze, and replacing it with a stronger solution. There is no difficulty in filling those tubes when the

hide has been dried, because then it is effected by capillary attraction. Mr. Chaplin will see then that it is possible that tanning liquor passing through a hide may tan the sides of the tubes through which it passes to the other surface and may fill for once the arteries and veins through which there is no current; but as the liquid cannot be renewed in the latter, the exhausted ooze remains in them until the apparently tanned hide is dry; when upon being introduced into water, the veins and arteries being untanned are immediately filled with water, and the leather is pervious. There is therefore no inconsistency in my statement. The eye is not a sufficient judge of the completion of the tanning process where part of the pores only have been tanned, because the distances between the tanned and untanned pores are only microscopic.

Mr. Chaplin states that the white slimy substance which oozes through the skin cannot be gelatine, because it tastes bitter and precipitates gelatine,and kindly offers me a means of satisfying myself that it is only tannin. I feel obliged, but have already analysed a portion of the white matter from a sample of the leather, and found it to be a compound of tannin, gelatine, and lime, and if that gentleman will make two more simple experiments, he will satisfy himself that I am right. First let him heat a bit on platinum foil or a glass plate; it will melt, then char, and will give off the well known smell of burning animal matter, which would not be produced were it only tannin, and he will find the ashes to be lime, which he may prove by a bit of moistened turmeric paper.

If the increased weight of my leather was owing to artificial or extraneous additions, itwould be dishonest to take advantage of the ignorant trader by selling it as leather; but it is not so: I retain the gelatine in the hide by preventing its being dissolved in the oozes; I tan the retained gelatine by giving it its due proportion of tannin and extractive, and thus increase the real matter of the leather, and consequently its durability, and its impermeability to water. It may be said that the shoemaker will lose by paying a halfpenny a pair more for his soles, but he will have more profits from customers who will have found the bene

fits of dry feet, and the economy of wearing shoes which have not required constant mending.

I perfectly agree that weight alone is not a sufficient test of the value of leather, nor have I advanced such an idea-the sentence ran thus: "I will engage to use his own liquors, whether from bark, valonia, divi divi, or terra japonica, and to return him 3 lb. per hide more than he can make by the ordinary mode."

Mr. Chaplin has misunderstood me when he believes me to object to the system of transfusion, merely because it was a "quick process." If the sentence is read as a whole, beginning after the word "weight," it will be seen that other circumstances besides quickness are given as reasons for the deficiency of weight and the permeability of leather tanned by transfusion.

In the course of a few days my specification will be enrolled, when the public will decide whether the new plan be or not a simple and philosophical means of surmounting the difficulties which the tanner has hitherto experienced. In the mean time I invite examination and trial of the few samples sent into the London market (which have been deficient in colour, however, not as a necessary consequence of the process, but from the difficulties attendant upon first experiments) and shall feel pleasure in answering any objections which may be urged with the urbanity and intelligence displayed by my present opponent. Yours, &c.

WILLIAM HERAPATH.
Bristol, March 1, 1838.

THE CONTROVERSY BETWEEN NAU

TILUS, O. N., &c.

Sir, I have sometimes been inclined to think that your able mathematical correspondent, O. N., in his first lucubrations in the Mechanics' Magazine was acting the character of the "Dougal creature" in Sir Walter Scott's historical novel of "Rob Roy;" and I am pretty sure Nautilus has by this time discovered that he very much underrated his scientific attainments when he reproved Kinclaven for condescending to notice some of his first essays in the

Mechanics' Magazine. But be that as it may, my present purpose is to make some remarks on Nautilus' last, and I must also say very intemperate, letter (763) inserted in your minor correspondence In the first place I must in form Nautilus, that at the time I wrote my last letter (761) I had not seen his (758) and I will also farther inform him, that even if I had seen it I certainly would have taken no notice of it. The task I

66

was called upon to perform was to answer a question put to me by O. N. (755). namely, "whether he, O. N., had mistaken my meaning in the answer he gave to my question" (743), which was why the perpendicular P N must fall upon D Z' produced, the latitude of the places of observation being 55..58 N." The answer O. N. gave to this question was, "if the perpendicular P N did not fall upon D Z' produced, then by a very simple calculation it might be shown that the zenith distance of Procyon would be greater than 90° &c." This was a simple and proper answer; in fact it was the only true answer that could be given to my question. And further, in justice to O. N. I must also state that the answer he gave to my second question which he deduced from the principles he so ably demonstrated in his letter (732) was equally judicious, and I trust, Mr. Editor, you will believe me, when I say, that had O. N. given an improper answer to either of my questions I would have lost no time in telling him so. But right or wrong Nautilus appears to have been determined to find O. N. in error, on my first question. Accordingly, in No. 751, he makes the following most illiberal remarks :

"O. N. has made another unfortunate slip, when he says in answer to Iver McIver's question of why the perpendicular P N must fall upon D Z' produced,' that if it did not, the zenith distance of Procyon would be greater than 90°."

This was the passage that O. N. called on me for my opinion upon (755) and this I gave; and I can with truth aver, in the most impartial way I could devise (761). Nautilus in continuation says, now a slight consideration of the particulars before given will show that from a to b the perpendicular P N must fall inside of the triangle, and not upon D Z produced, and yet that the zenith distance