EPEN LET Pons. 
NORMAL SOLUTIONS. 
RECENTLY Mr. James B. Dandeno published an articlet in which he 
accuses Kahlenberg and True? of having confused solutions containing gram- 
equivalents per liter with such as contain gram-molecules per liter. Because 
of the prominence given jto Mr. Dandeno’s article by publication in the 
BOTANICAL GAZETTE, | feel compelled to write this reply. 
Kahlenberg and True have used both expressions, gram-equivalent per 
liter and gram-molecule per liter, but they have not confused them. In the 
case of mono-basic acids and salts of mono-basic acids with monad metals a 
solution containing a gram-equivalent per liter is identical with a solution 
Containing a gram-molecule per liter, and hence in such cases the terms are 
perfectly interchangeable. This fact Mr. Dandeno evidently overlooked and 
so he saw great confusion where none existed. 
it will be necessary to take up Mr. Dandeno’s points somewhat in detail. 
The expression, “Chemically equivalent quantities (z. ¢. molecular quantities) 
of the different substances were not compared,” which Kahlenberg and True 
used on p. 85 of their article, occurs in the course of the general introduction 
and does not warrant (especially when taken together with the further dis- 
Cussion in the article) the conclusion of Mr. Dandeno that ‘‘they regard a 
§ram-molecule per liter exactly the same as a gram-equivalent per liter.” 
On p. g1 Kahlenberg and True say, referring to the various tables that fol- 
low, “In the first column appear the concentrations used expressed in gram- 
molecules or gram-equivalents per liter of the solution.” As both expressions 
actually appear, and are properly used, in the headings of the tables that fol- 
low, the above statement (which refers to all the tables in the article, except 
tables 18 and 1g concerning which special mention is made on p. 97) 7 Zts- 
self clearly does not warrant Mr. Dandeno’s conclusion that the authors 
regarded a gram-molecule per liter as exactly the same as a gram-equivalent 
per liter, 
Mr. Dandeno states that the normal solution of sulfuric acid used by 
Kahlenberg and True was “ purchased from the chemist” and that it was “a 
§tam-equivalent solution and was thought to be a gram-molecule solution.” 
No statement is made by Kahlenberg and True that any solution was “pur- 
chased from the chemist,” and Mr. Dandeno’s inference is wholly baseless. 
* Bor. Gaz, 32: 229, Oct. 1901. 2 Bot. GAZ. 22: 124, Aug. 1896. 
T90r] 437 
