\ the EDITOR'S • column •
Welch High Form T R I P L E B E A M BALANCE
L.T. Haltett, Editor
• High Sensitivity • Stainless Steel
rr\ o SPEED THE EXCHANGE of Scien-
-*- tific data, The National Bureau of Standards has adopted the International System of Units for use by its staff. From now on the Bureau will employ this system of units in all its publications except where use of these units would obviously impair communication. The International System of Units (designated 31 for Système International d'Unités) was defined and given official status by the 11th General Conference on Weights and Measures which met in Paris in October 1960. The SI is based on the following units: the meter (m) as the unit of length; the kilogram (kg) for mass; the second (s) for time; the ampere (A) for electric current; the degree Kelvin (° K) for temperature; and the candela (cd) for luminous intensity. Some of the more frequently used units of the SI and their symbols are listed in the table below.
Quantity Plane angle Solid angle Area Volume Frequency Density Velocity Angular velocity Accélération Angular accélération Force Pressure Kinematic viscosity
SI Unit Symbol radian rad steradian sr sq. meter m2 cubic meter m3 hertz Hz kilogram kg/m 3 per cubic meter meter per m/s sec. radian per rad/s sec. meter per m/s 2 sec. squared radian per rad/s 2 sec. squared newton N newton per N/m 2 sq. meter sq. merter m 2 /s per sec.
Capacity: 111 grams (with extra w e i g h t 2 0 1 g.) Sensitive to 0 . 0 1 gram Includes adjustable platform for specific gravity determinations
PAT. N O . 1872465
No. 4030
ONE-PIECE BEAM (PATENTED)
4030.
TRIPLE Form
ELECTROPOLISHED SURFACES
4031.
A U X I L I A R Y WEIGHT. For increasing the capacity of N o . 4 0 3 0 Balance to 2 0 1 grams. Each, $ 1 . 5 0
REVERSE ETCHED SCALES
on page 93 A
BALANCE. High Each, $ 2 7 . 5 0
4 0 3 0 C . PLASTIC COVER, For N o . 4 0 3 0 . Each, $ 1 . 6 0
Home Office: 7300 Ν. Under Ave., Depl. A-1, Skokie, III. 6007b SINCE I88O
THE
WELCH
SCIENTIFIC
COMPANY
Eastern Division: 331 Ε. 38th Street, New York, Ν. Υ. 10016 Western Divisions: 840 Cherry Street, San Carlos, Cal. 94070 13428 Wyandotte, North Hollywood, Cal. 9160S Manufacturers of Scientific Instruments and Laboratory Apparatus
Modern
design
improves l o w e r s cost
performance,
12" χ 12", $70 . . . 12" χ 24", $105 (115 or 230v)
TYPE 2 2 0 0 HOT PLATES THERMOLYNE ®
offer precision thermostatic control and fast heat-υρ
over the
entire stepless range to 700° F Write for literature and name of nearest dealer. THERMOLYNE
Continued
BEAM
C O R P O R A T I O N , D e p l . 4 7 8 , 2 5 5 5 Kerper B l v d . , D u b u q u e , I o w a Circle No. 84 on Readers' Service Card
VOL. 36, NO. 6, MAY 1964
·
91 A
