239 BOTANICAL GAZETTE [OCTOBER 
water. Some use the symbol x (meaning in chemistry a nor- 
mal solution) and say nothing about the method of prepara- 
tion, | 
There are two probable causes for this confusion. The ana- 
lytic chemists have differed in their use of solutions, (Allen, 
Chem. News 40: 239; also Analyst 13: 181, cited by Sutton 
18," p. 28.) Some (a very few) German chemists use a gram- 
molecule per liter and call it a normal solution. By far the 
greater number of modern analytical chemists, however, use a 
gram-equivalent per liter of solution as a normal solution, The 
physical chemist uses both the above mentioned methods of 
preparation, but is always clear as to the meaning, and calls 
only the gram-equivalent per liter the normal solution. Those 
who use the chemical symbol without explanation fall under 
some shadow of doubt arising from the above mentioned con- 
fusion. The work, however, may be faultless and the interpre- 
tation accurate. The theory of the separation, in aqueous solu- 
tions, of the molecules of compounds into ions is now a generally 
accepted one, and it is partly because of the actions of these 
ions, and of the dissociation of the molecule into ions, that there 
is great need of uniformity and of chemical accuracy in the 
preparation of solutions. Here are some definitions of normal 
solutions. 
1. Fresenius (2, p. 687): ‘Solutions of such strength that 
1000“ contain an amount of acid or base equivalent to one gram 
of hydrogen are normal solutions, e. ¢., 
HCl, mol. wt. 36.46, wt. in 1000° of solution 36.46 
eg. Oey « “ “ 
Na,CO, © Toast, oe: “4 #75304" 
Fresenius’ chemical table (p. 846) is based on the above men- 
tioned method of preparation. 
2. SUTTON (18, p. 28): ‘Normal solutions are prepared so 
that one liter of solution at 16° C. shall contain the hydrogen 
equivalent of the active reagent in grams (H =1),” ¢.g-° 
* See bibliography at end. 
