232 BOTANICAL GAZETTE [OCTOBER 
p. 78), is based on the gvam-equivalent per liter solution, and Le 
Blanc (7, p. 79), uses the symbol A to designate eguzvalent con- 
ductivity as distinguished from molecular conductivity, which is 
expressed by Ostwald as #. Moreover, Valson’s (24) law of the 
moduli (tables) is based upon gram-equivalent (not molecular) 
solutions, as well as almost all the analytical chemical tables now 
available. 
It is seen that the physical chemist recognizes two kinds 
of standard solutions, molecular solutions and equivalent solu- 
tions, calling the latter zormal solutions. The analytical chem-~ 
ist uses one kind of solution, the normal solution, z. ¢., the 
gram-equivalent per liter solution. 
The mistakes resulting from misinterpretation of normal 
solutions, and from a confusion of the terms gram-equivalent and 
gram-molecule per liter will be better understood if a few partic- 
ular cases be cited. Kahlenberg and True (5, p. 85), speak 
thus: ‘Chemically equivalent quantities (z. ¢., molecular quan- 
tities) of the different substances were not compared ;” also 
(p. 91), ‘expressed in gram-molecules or gram-equivalents 
per liter ;” showing that they regard a gram-molecule per liter 
as exactly the same as a gram-equivalent per liter, which, in the 
case of many of the substances referred to (¢.g., H,5O,), is not 
correct. What brings out more prominently the importance of 
the error is the fact that the solution of H,SO, (p. 92) was 4 
normal solution (purchased from the chemist), that is a gram- 
equivalent solution, and was thought to be a gram-molecule 
solution. Their results show that 4255 gram-equivalent per 
liter of H,SO, is as toxic as y,!5,; gram-equivalent per liter 
of HCl. In other words, the experiments seem to prove that 
the solution of H,SO, was what they shought it to be, though 
what zt was not. Heald (4, p. 125), referring to Kahlenberg 
and True, states that ‘‘in these experiments the solutions were 
prepared according to gram-equivalents.”” On pages 119-123 
of Kahlenberg and True we find written gram-mol. per liter. 
Similar mistakes were made by True (20, p. 184), where he 
says, referring to H,SO,, “and since it splits off two hydrogen 
