116 Lectures on the Results of the 



adduce other improvements introduced by chemistry in the smelt- 

 ing process ; but these will suffice to shew you that she has added 

 to human power by increasing production, while she has also eco~ 

 nomized both the time and the materials employed. 



2. Soap. — Soap is probably not older than the Christian 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 all the detailed descriptions of the bath and of washing, it is 

 never mentioned. Pliny describes its manufacture, but ascribes to 

 it as singular a use as that given to the potato by Gerarde, 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 be 

 eaten with sops and wines." So Pliny, in regard to soap, states, that 

 its main purpose was to dye the hair yellow, and that men 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 of 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 Napoleon 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 soda 

 made from salt is so great, that the manufacture of soap, and con- 

 sequently of soda, is enormously increased, and probably exceeds 

 ten times the largest quantity of barilla ever imported in one year 

 into this country. Its cheapness and excellence have also had a 

 prodigious effect on the manufacture of glass. 



3. Perfumery. — Much aid has been given by chemistry to the art 

 of perfumery. It is true that soap and perfumery are rather 

 rivals, the increase of the former diminishing the use of the latter. 

 Costly perfumes, formerly employed as a mask to want of clean- 

 liness, are less required now that soap has become a type of civili- 

 zation. Perfumers, if they do not occupy whole streets with 

 their shops, as they did in ancient Capua, shew more science in 

 attaining their perfumes than those of former times. The Jury 

 in the Exhibition, or rather two distinguished chemists of that 

 Jury, Dr Hoffman and Mr De la Rue, ascertained that some of 

 the most delicate perfumes were made by chemical artifice, and 

 not, as of old, by distilling them from flowers. The perfume of 

 flowers often consists of oils and ethers, which the chemist can 

 compound artificially in his laboratory. Commercial enterprise 



