206 CHEMICAL DISCOVERY AND INVENTION 



Another method depends on the action of strong sulphuric acid 

 on oleic acid, whereby it is converted into a mixture of solid 

 compounds which require subsequent distillation under reduced 

 pressure. 



No sooner had Sabatier made known the nature of his method 

 than numerous patents were taken out by other people with the 

 object of applying his principle to the hydrogenation of un- 

 saturated fats. 



The practical feature of these patents consists in the fact that 

 it is only necessary to add the catalyst, usually porous metallic 

 nickel, to the oil, to heat it to a moderate temperature, namely 

 from 200 to 250 C., and to inject hydrogen gas into the mixture. 

 The result is that the unsaturated oils present combine more or 

 less completely with hydrogen to form the corresponding 

 saturated fat, and thus at the end of the process a product is 

 obtained which has a melting-point considerably above the 

 melting-point of the material operated on. In fact an oily 

 substance is thus hardened into a fat which is solid at common 

 temperatures. The resulting hardened fats are of great com- 

 mercial importance, being largely employed especially in soap 

 and candle making. The following extract from a recent trade 

 report for the year 1913 1 indicates the manufacturer's view of 

 the position : 



" In the year 1913 the imports of the hitherto customary raw 

 materials for soap-making, such as tallow, palm oil, and cocoa- 

 nut oil, showed a drop of more than 6000 tons. But it must not 

 be concluded from this that the production of British soaps 

 decreased in that year, because the new hardening process has 

 also given to certain other fatty substances, such as whale oil 

 and linseed, which formerly were scarcely of any account, a 

 great importance for the soap industry. This process is all the 

 more important for the British soap industry because through 

 the establishment of numerous soap factories in countries which 

 formerly supplied basic materials (South Africa, Australia, 

 Argentina, Japan, etc.), these materials are now employed locally 

 instead of being sent to Great Britain. Thus the hardening 

 process has prevented an enhancement of the prices of the basic 

 materials, and of the soap itself, which would have considerably 

 restricted both the consumption and the production." 



The production of the enormous quantities of hydrogen 

 1 Messrs. Bigland Sons and Jeffreys, of Liverpool, 



