CATALYSIS AND CATALYSTS 205 



conflict of evidence here, and time only will show what further 

 light can be obtained in this direction by research. 



We may now turn to the consideration of the important 

 practical applications which have arisen out of these apparently 

 recondite investigations. In the first place it is perhaps not 

 inappropriate to observe that they supply a satisfactory answer 

 to those persons who are often disposed to enquire as to the 

 utility of this or that piece of pure scientific work which seeks to 

 extend knowledge without reference to the further use of it. 

 Scientific literature abounds with examples, but this deserves 

 remark, because it is so recent as to be still in process of develop- 

 ment. But there is another reason for noticing the present case 

 attentively, and that is that it serves as an example of the 

 common failure of the discoverer to participate in the commercial 

 profit which is made of his discovery. Professor Sabatier has 

 shown the chemist and manufacturer how the element hydrogen 

 may be made to unite with a great diversity of substances, by a 

 process which is easily carried out and which involves the use of 

 no costly materials. 



A large proportion of vegetable oils and some animal fats are 

 liquid at the common temperature of the air. They are, there- 

 fore, of smaller value for many purposes than the fats which are 

 solid under the same conditions. Consequently many attempts 

 have already been made to act on the oils in such a way as to 

 convert them more or less completely into solid substances. 

 It should be explained that most of the oils consist essentially 

 of a compound called olein, which is the ester or compound ether 

 of glycerine with oleic acid. The solid fats are similar compounds 

 derived from stearic or palmitic acid. Stearic acid is so named 

 from the Greek word crreap, tallow. Palmitic acid occurs 

 abundantly in palm oil. Now these latter acids are what the 

 chemist calls saturated compounds, that is they contain the 

 carbon, hydrogen, and oxygen, of which they are composed, in 

 such a condition that they fully satisfy their mutual attractions 

 and cannot enter directly into any further chemical union. But 

 olein is unsaturated and can unite with two atoms of hydrogen, 

 forming stearic acid. 



The most practical of the older attempts to produce a solid 

 fat from oil was based on the fact, discovered long ago, that in 

 contact with nitrous acid olein and oleic acid are converted into 

 solid compounds, called respectively elai'din and elai'dic acid. 



