A HARD-WORKING DIET. 349 



substance results in the formation of ammonia, then 

 if the theory be correct, the heavier the work done the 

 more should be the amount of ammonia given off. 

 But several trials showed this does not take place. 



The difficulties led to many experiments in many 

 lands. 



The correlation of the physical forces, now so 

 familiar to everybody, was then but dimly seen or 

 guessed at rather than seen in the far distance. 

 But while many of Liebig's pupils and followers were 

 experimenting on themselves and other people as to 

 the connection between food, work and the amounts 

 of carbonic acid and ammonia given off, Joule was 

 working out questions connected with the conversion 

 of heat into motion and motion into heat. 



At last, in 1866, Frankland, taking the results of 

 many experiments, and his own laboratory work, as 

 his data, worked out the figures showing the CON- 

 NECTION BETWEEN MUSCULAR FORCE AND THE 

 OXIDATION OF CARBON AND HYDROGEN, and at a 

 lecture at the Royal Institution, made the triumphant 



announcement HERE IS THE SOURCE OF MUSCULAR The source of 



muscular 



POWER. (For " hard work, see p. 358.) power. 



Liebig, loving truth more than self-glorification, 

 eventually recognised his former mistake, and the 

 controversy that existed has passed into oblivion. 



The same rough and ready way of showing that How to ex- 

 carbonic acid is formed by the oxidation of candle fat recognise the 

 (p. 343), will suffice to show that carbonic acid is given thestudy! 

 off in the breath. It is only requisite to blow through 

 a tube into clear lime water to see by the formation 

 of carbonate of lime that there is much carbonic acid in 

 the air we breathe out. Again, it requires no apparatus 



