1915] 



on Science and Industrial Problems 



119 



Another phrase from the patent specification which would at 

 once attract the attention of the experimental chemist is the 

 following: — "The quantity of the nickel thus added and the 

 temperature are immaterial, and will only affect the duration of the 

 process." 



That may be so, but obviously there must be one set of conditions 

 which 'is best suited to making the process an economic success, 

 and that is, of course, what the manufacturer desires. There must, 

 therefore, be a definite temperature, and a certain proportion of 



Fig. 4. 



nickel which will give the best results, and these important factors 

 can only be determined by making numerous experiments. 



These two points are well illustrated by the curves in Fig. 3, 

 which show the great importance of selecting a definite proportion 

 of the catalyst, and also, in common with previous curves, the effect 

 of temperature on the absorption of hydrogen. With • 5 per cent 

 of nickel there was practically no absorption of hydrogen, even on 

 raising the temperature to 250° ; with 1 per cent of nickel absorp- 

 tion was slow at 180°, increasing rapidly on raising the temperature 

 to 250°, whereas w^ith 5 per cent of nickel the absorption was at the 

 end of seven and a-half hours considerably greater at 180° than it 

 was at 250°, when using only 1 per cent of nickel. 



Y 2 



