564 



ILLUSTRATIVE EXPERIMENTS 



CONVERSION FACTORS 



94. Graphic Conversion of Sorensen's />H( — log (H) ) into Concentrations 

 of Hydrogen Ions and the Reverse (Roaf, Journ. of Physiol.). 



Fig. 115 is a graph whereby the logarithmic notation of Sorensen can be 

 converted at sight into true concentrations. It would be advisable to redraw 

 the figure on semi-logarithmic paper and so enable the reading to be taken 



[H-] or C„ = 10 ■" - log [H-] or pH = » + . . . 

 Fig. 115. — Graph for conversion of pH to (' ^^. 



to two places of decimals For example, to convert yjHG-T into C„, p\i — 6, 

 i.e. C„ = 10^ ; 0-7 cuts the diagonal line opposite 0-2 ; therefore 



/;Hof fi-7 = C„ of ()-2 X 10-«. 



95. Estimation of the Surface Area of the Body. 



Rubner announced that the amount of heat 'produced by an animal is 

 proportional to its superficial area. This law of surface area has rendered 

 necessary the accurate determination of the skin surface in most metabolism 

 experiments. 



