VELOCITY OF REACTION. HOMOGENEOUS SYSTEMS 55 



According to the figures of Terroine K does not change 

 more than 10 per cent (the last value, as there are only 3.5 

 per cent of the matose left, is too unreliable to be used for 

 the calculation). But in the same memoir, on p. 4, Henri 

 gives values for a 2 per cent solution of maltose for 

 which the values of K change between 3i9-io~ 5 and 

 489 io~ 5 i.e. 53 per cent. The errors of observation must 

 therefore be very great, and the figures should not be ap- 

 plied to delicate calculations. Still greater is the disagree- 

 ment in the figures of Armstrong, 1 who finds that the con- 



MALTOSE 5 % AT 30 (E. F. ARMSTRONG) 



stant K ly calculated from the formula for monomolecular 

 reactions, sinks with the progress of the reaction; whereas 

 Henri finds that K, calculated from his formula, is nearly 

 constant; i.e. that K as is seen in the figures given above, 

 increases very rapidly with the progress of the reaction, and 

 this is valid not only for 2 per cent, but in a still higher de- 

 gree for 4 per cent and 6 per cent solutions. 2 



Armstrong has communicated additional measurements 



1 E. F. Armstrong: Proc. Roy. Soc. 73. 508 (1904). 



2 Brown and Glendinning (Journ. Chem. Soc. 81. 388, 1902) find that the 

 formula of Henri's is valid even for the hydrolysis of soluble starch by means 

 of diastase. 



