APRIL 12, 1912] 
and less than 6. The most useful table, one 
which precludes the necessity of rearrange- 
ment or recalculation, is one which includes 
all three of these possible values. For the 
most common orthorhombic minerals such a 
table has been arranged with the values of a 
in increasing order of magnitude, the corre- 
sponding values of c and the mineral names 
being placed in parallel columns. Thus each 
mineral appears three times, and the value of 
@ accepted by convention is underlined. The 
corresponding value of ¢ in the parallel col- 
umn is a very useful check in tracing the un- 
known mineral. 
If a monoclinic mineral is held with the 
greatest possible number of faces vertical, the 
most probable mistake in orientation is the 
interchange of a and c axes. Hence the table 
is made to include both a and c as possible 
values of a, 7. e., each mineral appearing twice 
in the table. 
Would such tables, enlarged to include all 
minerals for which axial ratios have been de- 
termined, be useful accessories in the work of 
erystallographic mineral determination with 
the reflecting goniometer? Would tables 
further enlarged to include artificial crystals 
be of use to the chemical erystallographer ? 
Before undertaking such a task one wishes 
to know if it is worth while, and for this 
reason the questions are presented. Sugges- 
tions, and the utmost freedom of criticism by 
teachers of crystallography, are invited. 
Ottver Bow rs 
DEPARTMENT OF GEOLOGY AND MINERALOGY, 
UNIVERSITY OF MINNESOTA 
HOUSE AIR 
To tHe Eprror or Science: I had occasion 
recently to consult the issue of Science for 
September 29, 1911, and read for the first time 
the letter on “ House Air” from Professor J. 
Y. Bergen, of Cambridge. 
He makes this statement regarding the 
ventilation obtained from a hot air register: 
The ventilation . . . is much better than can be 
obtained in summer by opening a single window 
to its full height. 
It is doubtless known to him and should be 
SCIENCE 
577 
more widely known that it is better to pull the 
window down a couple of inches from the top 
and up from the bottom when ventilation is 
required than to open either half only. The 
truth of this statement can easily be tested by 
holding a lighted candle at the window open- 
ings. 
G. L, Mannine 
ROBERT COLLEGE, 
January 23, 1912 
QUOTATIONS 
MOST RECENT INVESTIGATIONS ON THE DETERMINA- 
TION, PRESERVATIVE ACTION AND ADMISSI- 
BILITY OF THE USE OF BENZOIC ACID* 
PART IT 
I now come to the most important part of 
my work—a critical summary of the three de- 
tailed investigations on the effect of benzoic 
acid and of benzoates on man which have been 
carried out during the last four years and 
which now furnish us that broad basis, which 
I have always desired, necessary for the for- 
mation of an intelligent opinion. First, there 
are two great works from the American De- 
partment of Agriculture; one carried out by 
H. W. Wiley,’ in 1908, the other by a commis- 
sion, under the chairmanship of the distin- 
guished chemist, Ira Remsen, consisting of the 
three well-known American scientists, Pro- 
fessor Russell H. Chittenden, of Yale Univer- 
sity; Professor John H. Long, of Northwest- 
ern University, and Professor Christian A. 
Herter, of Columbia University, New York. It 
seems strange that a great government should 
publish two books, one right after the other, 
dealing with the same subject-matter; and we 
seek in vain, in the second large volume of 
461 pages, for a word of explanation of this 
surprising fact. Wiley’s work is simply ig- 
1 Translated from the Chemiker-Zeitung, Cothen, 
November 28, 1911, pp. 1314-17. 
2Part I. (Chem. Ztg., 1911, pp. 1297-99) is a 
summary of the articles dealing with the isolation, 
qualitative and quantitative determination, nat- 
ural oceurrence in plants, preservative action, use 
and toxie effects of benzoic acid. 
J. Soc. Chem. Ind., 28, 67 (1909). 
