1853.] 



instance terra japonica, cutch, catechu, and dividivi, produce their 

 effects in half the time, but the leather is said not to be so dura- 

 ble. With sumach light skins may be tanned in twenty-four 

 hours, and with the aid of alum even in one hour; but the result- 

 ing manufactures are not preferred to the old processes. Atmos- 

 pheric and hydrostatic pressure have been used to hasten the 

 absorption; the refined laws of Endosmis and Exosmosis hive 

 been called in to accelerate the process; heavy rollers have 

 squeezed the solution through the pores ; but all these methods 

 ha\e at the best but a doubtful success. Leather-manufacturers 

 meet men of science by the well-founded assertion that the 

 resulting leather is too porous, too hard or too soft, or not suffi- 

 ciently durable ; and they revert to their old traditional modes of 

 preparation. I allude to these failures the more especially to show 

 that there is a wide chasm between the chemist's laboratory and 

 the workshop, — a chasm which has to be bridged over by the 

 united aid of the philosopher and the manufacturer. One without 

 the other does not suffice; but both, working together, may 

 achieve great results. Yet, in bridging over this chasm, they 

 must act on a common plan. If the manufacturer build his half 

 without understanding the principles of construction employed 

 by the other, the sides of the bridge may indeed meet, but they 

 are not constructed to receive tlie binding influence of the key- 

 stone, and the arch must give way and tumble down. 



Having thus shown the comparative failure of Chemistry in 

 revolutionizing this important manufacture, let me take one or two 

 instances from it to prove that, in the details of the working, it 

 has been of use in economizing time and labour, and in affording 

 new uses to compai'atively valueless objects. In removing the 

 hair from the hides, previous to tanning, it was customary to 

 shave it with a knife. This process was tedious and imperfect, 

 and the following simple one is now used. Lime-water dissolves 

 the bulbous root of the hair, when the hides are immersed in it 

 for some time, and the hair may then be readily removed by a 

 blunt instrument. By this simple process one man can remove 

 the hair from a hundred kid-skins in an hour. Still the immer- 

 sion requires several weeks, while the addition of red orpiment to 

 the lime, as practised by the sheep-skin manufacturers of France, 

 reduces the time to a few hours. 



When goat-skins are tanned for morocco leather it is necessary, 

 in order to adapt them for dyeing, to remove the lime absorbed 

 by the last operation. A solution of album grcecum cleanses the 

 pores effectually, leaving them so spongelike that air can readily 

 be forced through them. Hence the jiroces, of tanning is ren- 

 dered much easier, being in fact completed within twenty-four 

 houra ; while the leather is rendered fit to assume the colour's so 

 characteristic of morocco. About fifty persons are employed in 

 London to collect the sweepings of dog-kennels for this purpose, 

 and many more in applying them ; and I am informed, by Mr. 

 Bevington, that the sum annuall}' paid to the collectors and 

 workmen employed in using this apparently worthless substance, 

 is not less than 5000^. in the metropolis alone. 



The currier shaves leather to render it of equal thickness, and 

 the shavings were treated as waste, scarcely fit for the manure- 

 heap; but Chemistry has shown that they contain much nitrogen, 

 whicli renders them well adapted for the formation of the beauti- 

 ful colour known as Prussian blue. 



Soap. — Soap is probably not older than the Chiistian era, for 

 the soap of the Old Testament seems to have been merely alkali. 

 Profane history, previous to Christ, does not allude to soap ; and 

 in aU the detailed descriptions of the bath and of washing, it is 

 never mentioned. Pliny describes its raanufactui'e, but ascribes 

 to it as singular a use as that given to the potato by Gerard, who, 

 in his " Herbal," assures us that it " is a plant from America, 

 which is an excellent thing for making sweet sauces, and also to 



CORRESPONDENCE. 



187 



be eaten with sops and wines;" so Plin}', in regard to soap 

 states, that its main purpose was to dye the hair yellow, and that , 

 meu used it for this purpose much more than women. Gradually 

 its use became more extensive, and its manufacture considerable. 

 Soap generally consists of a fatty acid, combined with the alkali 

 soda. This soda was imported from Spain under the name 

 of barilla, itself the ashes of plants grown near the sea. As these 

 plants derived their soda from the sea, near which they flourished, 

 Chemistry — though singularly enough in the person of Napo- 

 leon Bonaparte — suggested that it might be artificially made 

 from sea salt. A process for this was perfected, and soda derived 

 from salt has now replaced barilla. From 1829 to 1834 the 

 average annual import of barilla was 252,000 cwt; it is now 

 almost nothing. But besides this substitution, the cheapness and 

 comparative purity of the soap, and consequently of soda, is 

 enormously increasei.1, and probably exceeds ten times the largest 

 quantity of barilla ever imported in one year into this ccuntry. Its 

 cheapness and excellence have also had a prodigious efi'ect on the 

 manufacture of glass. 



Chemistry has thus produced great economy and increasing 

 power of production to the manufacturers of soap, by furnishing 

 them with soda prepared directly and artificially from salt, instead 

 of through the organism of plants. This, however, is only one of 

 the benefits conferred on this manufacture by Chemical Science. 

 The fiscal regulations of foreign countries rendered their tallow 

 and fats expensive to British industry. Russia, with almost a 

 monopoly of tallow and linseed oil, thought it good policy to sell 

 them at high prices. But Chemistry pointed out that vegetables, 

 as well as animals, produce similar fats. The fat of beef and 

 mutton exists in cocoa beans ; human fat in olive-oil ; that of 

 butter in palm-oil ; and horse fat and train-oil are in many oily 

 seeds- Was it, then, necessary to submit to the high prices of 

 Russian tallow ? Now, palm and cocoa-nut oil largely replace 

 the fat of the Russian oxen and sheep, although the cheap 

 importation of similar fats from Australia and South America 

 has rendered the substitution less necessary. 



CORRESPONDENCE. 



Natural History Society cf Alontreal. 



We have great pleasure in giving insertion to the accompanying 

 communication from Major LachJan, vindicating the Natural History 

 Society of Montreal, from imputations which he considers to have been 

 cast upon it by our introductory remarks to tliis Journal, page 2. That 

 the gallant President misunderstood the tenor of the passage he refers 

 to, will be evident to any one who dispassionately considers it ; far 

 from any disrespect being intended by our enquiry, the contrary is 

 expressly stated. His own Address to that Society, in March, 1852, 

 commented in much stronger terms than a stranger would venture to 

 do, upon its "non-success," and on the spirit of indifference which 

 appeared to have fallen upon it. Such a fact in the previous experience 

 of a Canadian Society, was too important to be left out of view, in con- 

 sidering jthe probable prospects of the Canadian Institute ; but we 

 really thought we had alluded to it in terms to which the most sensi- 

 tive could attach no offence. "We are, however, too well aware of the 

 ardent support which the gallant Major has given for many years, to 

 every proposal having in view the development of scientific pursuits in 

 Canada, to be surprised that such an allusion to a society presided over 

 at present by himself, should meet with a warm response : and too well 

 pleased to have the character and condition of our brethren in the 

 Lower Province, placed in a favorable light before our readers, to feel 

 the smallest hesitation in making the fuUest amende for any thing 

 unjust in our remark. In fact, the expression that neither the Natural 

 History Society of Montreal, or the Literary and Historical Society of 

 Quebec, have practically exercised any influence in Upper Canada, 

 does appear to be somewhat too strong : the former by its prizes and 



