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This burette, while sacrificing none of the accuracy possessed by the Hempel, Orsat or McIntosh-Elliott, very greatly decreases the time necessary for an analysis. A complete analysis of coal, water, natural fuel, producer, acetylene, or gasoline gas, comprising determinations of any or all of the following constituents: carbon dioxide, illuminants, oxygen, carbon-monoxide, methane, hydrogen and nitrogen, can be made in from twenty to twenty-five minutes. The saving in time is effected by the elimination of the necessity of shifting the gas from one portion of the apparatus to another. With each outfit we send a 20-page treatise by Mr. Morehead on “ Industrial Gases," giving full directions for using the apparatus.

Furnished complete with Support, Aspirator Bottles and Rubber Tubing, as illustrated. Also furnished complete as illustrated, but the Burette supplied with Water Jacket for securing constant temperature.

Further information and prices on application.

1

E. H. SARGENT & CO.

IMPORTERS, MAKERS AND DEALERS IN CHEMICALS AND CHEMICAL APPARATUS OF HIGH GRADE ONLY

155-165 EAST SUPERIOR STREET

CHICAGO, ILL.

CADMIUM STANDARD CELLS

u

For use with potentiometers, electrometers, aad ballistic galvenometers, or wherever else a precision standard of electromotive force lo needed.

Negligible Temperature Coeficient.

Highly Constant E, M, F.
Contents bermetically realed in glass so that lowering of electro-
motive force due to evaporation is impossible.

Mounted in moulded box, or unmounted.
My comparison certificate accompanies cach cell without charge
Bureau of Standards certificate extn.

On November 13, 1916, three normal cadmium cells made by me
were certified by the
Bureau of Standards as differing from

their group of reference cells by less than one part in one hundred thousand, 21 three having the same value.

On March 30 1930. after the lapse of three years and four months the same three cells were again compared by the Bureau of Standards. The maximum difference among the three was less than one part per hundred thousand, and the maximum difference from their oertibed value of 1916, was less than one part per bundred thousand.

In other words, these cells showed a degree of constancy to all intents equal to that considered most bighly satisfactory, if not remark. able, in the very best type of precision resistance standarde (See Bul. Bur. of Stand. Vol. 5, No. 3, D. 427.)

The cells in question were in nowise special. They were made of the materials regularly prepared by me, and were set up with no greater are than that constantly employed in the maklag of my stan. dards.

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Marion Eppley,

AM, Ph.D.)
Physico-Chemical Apparatus.

NEWPORT, R. I.

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No Laboratory Equipment is complete without some variable resistances. To maintain the high standard of your outfit wo suggest the addition of some

"Becbro" Sliding Contact Rheostats

(Tubular and Stone Types)

Thousands of these rheostats have been manufactured and sold by us (the original American Manufacturers) to almost all Universities, Colleges, Technical Schools and Industrial Concerns and have always given entire satisfaction.

Write for Bulletin C-5 BECK

3640-42 North Second Street

Philadelphia, Pa.

BROS.

Spencer Microscope, No. 44H

With side-fine adjustment, lever type, is
An Ideal Instrument for

Laboratory Use
It is not only its accuracy and utility-it is some-
thing in the finish, even more in the design; and in
addition to all these, it is those little things-clever
little devices, which accomplish the same end but in
a better way–exactly the way the laboratory worker
wants them. These are the distinctive features of
Spencer microscopes.

It has become a standard for College and University laboratory work because of two special advantages:

I. A side fine adjustment with a

screw which has 34 threads
engaged at all times, in-
stead of but the customary
one thread.

44H Microscope completely II. A side fine adjustment which equipped with 6X and 10x oculars, has a “Lateral-Travel”— tives, triple nose piece, quick screw

16 mm., 4 mm., and 1.8 mm. objecan index to its position rela- substage with condenser and iris tive to its limits.

diaphragm.

44F Microscope, same equipThese coupled with other advan

as above but without the tages, optically and mechanically

1.8 mm. objective and with double make it an ideal microscope.

nosepiece instead of triple.

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H

ment

We Carry an Extensive Stock of Spencer

Microscopes and Accessories

Fine Adjustment

BRAUN-KNECHT-HEIMANN-CO.

FOUNDED 1852 584 Mission Street

SAN FRANCISCO, CAL., U.S. A. Scientific Apparatus of Every Description for all kinds of Laboratories. We

Specialize in Laboratory Equipment for Universities, Colleges,
Schools, Missions, Hospitals, Assay Offices, etc.

Chemicals — Acids Glassware
Inventors - Manufacturers — Exporters - Importers

“ We know how to pack for Export" Cable Address "BRAUNDRUG”

Los Angeles House All Codes Used

THE BRAUN CORPORATION

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The Silverman Illuminator

"A New Eye for the Microsoope" a-Shows more detail. b-Presents a clearer and

better defined picture
to the eye and the

camera.
C-Produces several novel

methods of illumina

tion. d-Save very much valu

able time. Prevents eye strain, eye

fatigue and brain fag. f-Can be lowered into deep,

hollow objects.
8–Gives excellent results

for very low power
work, also higher mag-
nifications, and in oil

immersion work.
h-Can be used with any

microscope, ordinary or

binocular. A small circular tube lamp surrounds the objective and furnishes diffused and uniform illumination directly where it is needed. For sale by all the better dealers

Write for Bulletin 45-B LUDWIG HOMMEL & CO. 530-534 Fernando St. Pittsburgh, Pa.

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A comparative test will speedily prove its excellence. Make one! We will be glad to furnish samples on request. All dealers in laboratory supplies carry these papers in stock.

H. REEVE ANGEL & CO.

INCORPORATED 7-11 Spruce Street

New York, N. Y.

Solo Mill Representatives for the United States,

Canada and Mexico

NEW SERIES
VOL. LIII, No. 1382

FRIDAY, JUNE 24, 1921

SINGLE COPIES, 15 CTS.
ANNUAL SUBSCRIPTION,

$6.00

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BINGHAM & CEN Viscometer and F tometer

SIMI D FORM
Especially into for the testing of
Paints, Greases, (z Varnishes.
This apparatus

used, however, for testing the viscosi ny form of liquid, besides being ada or determining the plasticity of all plastic materials for which the initial pressure required is not more than that of a 10 foot water column.

The above is a simplified form of the apparatus (also supplied by us), which is recognized by the Bureau of Standards as the standard instrument for the determination of viscosity and plasticity.

The simplified apparatus consists essentially of the following parts:

2 pipe reservoir for stabilizing
pressure..

$80.00.
Water Bath with cover for

regulating temperature. . . $22.50. Plastometer (Viscometer) with

2 wrenches and key...... $60.00. Besides the above essential parts, auxiliary apparatus may be ordered as desired.

For information in regard to auxiliary apparatus, and for further details, see E & A Bulletin No. 277, also Bureau of Standards bulletins Nos. 278 and 298, Proc. of A.S.T.M. Vols. 18 and 19; also Jour, of Amer. Chem. Soc., Vol. 38, P. 40, 1916, etc.

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