SCIEN CE—ADVERTISEMENTS 
The Philippine 
Journal of Science 
ALVIN J. COX, M.A., Ph.D., General Editor 
Published by the Bureau of Science 
of the Government of the 
Philippine Islands 
A Periodical Devoted to the Scientific and.Commercial 
Interests of the Tropics 
The Journal, now in its twelfth volume, is issued in four 
sections. Hach section consists of six numbers a year, in 
Benarately, paged and indexed, and is a complete publication 
in itself. 
YEARLY SUBSCRIPTION RATES 
Section A. Chemical and Geological Sciences and 
the Industries................::::000200 reprooacbodecceab soacodaacecd $2.00 
Section B. Tropical Medicine : 
Section C. Botany 
Section D. General Biology, Ethnology and Anthro- 
pology 2.00 
The four sections to one subscriber 
A complete list of the publications of the Philippine Bureau 
of Science and a sample copy of the Philippine Journal of 
Science will be sent upon request. 
Subscriptions and orders for publications should be sent to 
THE BUSINESS MANAGER 
Philippine Journal of Science 
Bureau of Science MANILA, P. I. 
Publications of 
Carnegie Institution of Washington 
The publications of the Institution now number over 350 
volumes, the subjects including Anatomy, Archmology, Astron- 
omy, Botany, Chemistry, Economics and Sociology, Embry- 
ology, Experimental Evolution and Heredity, Engineering, 
Folk-Lore, Geology, History, International Law, Literature, 
Mathematics, Medicine, Nutrition, Philology, Physics, Zool- 
ogy. Classified and descriptive lists will be sent postpaid 
on application. 
No. 78. SHaw, J. B. Synopsis of Linear Associative Algebra: 
Report on its Natural Development and the Results 
Reached up to the Present time. Quarto, 145 pages. 
Price, $1.50. 
No. 120. Drcxur, F. F. The Symmetric Function Tables 
of the Fifteenthic. Quarto, 21 pages. Price, $1.25. 
No. 105. Leamer, D. N. Factor Table for the First Ten 
Millions, containing the smallest factor of every number 
not divisible by 2, 3, 5 or 7 between the limits 0 and 
10017000. Folio, xiv-+476 pages. Bound in Leather and 
Buckram, $20.00; Unbound, $18.00. 
No.165. Lpamer, D.N._ List of Prime 'Numbers from 1 to 
10006721. Folio. xvi+133 pages. Price, $5.00. 
RECENTLY ISSUED 
No. 245. Hepricx, H. B. Interpolation Tables or Tables of 
Proportional Parts, containing the products to the nearest 
unit of all numbers from 1 to 100 by each hundredth 
from 0.01 to 0.99 and of all numbers from 1 to 1000 by 
each thousandth from 0.001 to 0.999. Folio. 149 pages. 
Price, $5.00. 
IN PRESS 
No. 256. Dicxson, L. E. History of the Theory of Numbers. 
Octavo. Vol. I. Divisibility and Primality. In press. 
All communications should be addressed to 
CARNEGIE INSTITUTION OF WASHINGTON 
WASHINGTON, D. C. 
Handy 
Resistance Units 
These are furnished in single value blocks, 
ranging from 0.1 ohm to 10,000 ohms. Blocks 
for all values are uniform in size, and can 
readily be arranged in groups to build up any 
desired resistance. Adjustment is made to 
within 1/20 of one per cent. 
We have just issued a new Circular (No. 10), 
describing and listing these units. Write 
for it. 
Circular No. ro also describes a new two-value 
Unt, especially designed for teaching purposes, 
to check up students on reststance measurements. 
PYROLECTRIC INSTRUMENT Co. 
Pyrometric and Electrical Peeciston Instruments 
636 EAST STATE STREET 4 (TRENTON, N. J. 
E. F, Northrup, President and Technical Adviser 
GAS—GAS 
The “Detroit” 
Combination Gas Machine 
Automatically makes the best 
and cheapest gas for 
Laboratory Uses of Every Character 
Heating—Cooking—Lighting 
Over 30,000 in daily use 
Descriptive catalogue and names of users in your 
locality sent on request 
THE DETROIT HEATING & 
LIGHTING CO. 
612 Wight St. Detroit, Mich. 
Established 1868 
