SCIENCE—ADVERTISEMENTS 
COMPTON QUADRANT 
ELECTROMETER 
Described in‘Circular No. 6 
PYROLECTRIC INSTRUMENT Co. 
Pyrometric and Electrical Precision Instruments 
148 EAST STATE STREET TRENTON, N. J. 
E. F. Northrup, President and Technical Adviser 
Tycos 
Temperature Instruments 
Indicating—Recording—Controlling 
Mercurial, Recording and 
Index Thermometers for 
all industrial and Jabor- 
atory applications. 
Electric Contact Ther- 
mometers. 
Temperature, Pressure and 
Time Regulators. 
Mercury Column Vacuum 
Pressure and U Gauges. 
ee Metal Rare aa and 
‘adiation Pyrometers. 
Fery Radiation Pyrom- Tycos Pyrometer 
eters. High Resistance Wall Type Indicator 
eon. 
Tene ngtastn-| In selecting the proper 
ments. Z equipment for the measure- 
ment of high temperatures, 
progressive manufacturers in- 
variably choose Tycos Pyro- 
Aneroid Barometers 
Mercurial Barometers 
Recording Barometers 
Pocket Compasses 
Surveying Compasses 
-Rain Gauges. meters. 
Anemometers. 
a Meters. hs. May we send you our cat- 
Hand Levels. alogues which explain these 
Aviation Barometers. 
Inclinometers. Jycos Instruments fully? 
Sphygmomanometers. 
Fever Thermometers. ’ 
Urinary Glassware. _ | 1 aylor Instrument Co.’s 
Thermometers of all kinds : 
for home and General Use. ROCHESTER, N. Y. 
Memoirs of the Wistar Institute of Anatomy and 
Biology. No. 6, 1915 
THE RAT 
Data and Reference Tables. 278 Pages. 89 Tables. 
Bibliography. ; 
Compiled and Edited by HENRY H. DONALDSON. 
Postpaid, $3.00. Ear ; 
The Wistar Institute - Philadelphia, Pa. 
OPTIC PROJECTION 
Principles, installation and use of the Mag-c Lantern, Opaque 
Lantern. Projection Microscope and Moving Picture Machine; 
700 pages, 400 figs. By.Smon Henry Gaae, B.S., and 
Heyex Puerrs Gacn, Pa.D. Postpaid, $3.00, 
THE COMSTOCK PUBLISHING CO.,Ithaca,N Y. 
MARINE BIOLOGICAL LABORATORY 
WOODS HOLE, MASS. 
Biclogical Material : 
1. Zoology. Preserved material of all types of animals 
for class work and for the museum. 
2. Embryology. Stages of some invertebrates, fishes (in- 
eluding Acanthias, Amia and Lepidosteus), Amphibia, and’ 
s0me mammals, 
3. Botany. Preserved material of Algae, Fungi, Liver- 
worts and Mosses. Price lists furnished on application to 
GEORGE M. GRAY, Curator, Woods Hele, Mass- 
JULIEN’S POWER LATHES 
COMPACT—ACCURATE—DURABLE 
Use of Geologists, Mineralogists, etc., in SLICING 
and POLISHING all hard substances, rock, etc., and 
in preparation of MICROSCOPIC THIN SECTIONS. 
GUSTAVUS D. JULIEN 
3 Webster Terrace NEW ROCHELLE, N. Y. 
Wm. Gaertner & Co. 
Standard Apparatus of { 
New and Improved 
Precision Measuring In- 
struments of great variety mometers. 
5345-5349 Lake Park Ave. 
Prof. F. A. Saunder’s Wave Projec- 
tion Slide 
Designs 
Reading Device for Ther- 
Catalogue No. 
C1365, 1.80 
Chicago 
