: the EDITOR'S ; column •
WELCH DUO-SEAL VACUUM PUMPS
L.T. Hallett, Editor
TTjre did not realize the extent of ' ' activities in t h e U.S. and abroad of electron microscopists until we received a communication from T. G. Rochow, A. M . Thomas, and ΛΙ. C. Botty, American C y anamid Co. As D r . Rochow and his associ ates note, the growth of electron microscopy and that of the Electron Alieroscope Society of America ( EAISA ) arc very closely related. By 1959 E M S A had a membership of about 850. Λ [embers of E M S A are active not only with regard to promoting a n d developing this field through scien tific and technical meetings in t h e U.S. and abroad b u t also through giving specialized courses in the use of t h e instrument. 20th Anniversary. EMSA will celebrate its 20th anniversary in 1962. This date coincides with t h e quadrennial meeting of the I n t e r n a tional Congress for Electron M i croscopy. E M S A will be host for this meeting at the University of Pennsylvania in Philadelphia (Au gust 29 to September 5, 1962). E M S A h a s an active meeting program. T h e 1960 session will be held a t M a r q u e t t e University, Mil waukee, August 29 to 31. In 1961, the E M S A meeting will be held in Pittsburgh (August 23 to 2 6 ) . Interest of members is high. I n 1959, for example, approximately 40% of t h e membership attended the meeting at Ohio State Univer sity. T h e program consisted of three symposia, 100 contributed p a pers, and 15 micrographie exhibits. One of t h e symposia, presented in cooperation with t h e American Cancer Society, covered some prob lems in cancer research. T h e other symposia covered elementary tech niques a n d ceramic materials. Topics included in t h e general p a -
Welch Pumps are best because : Every pump is triple tested. Specified performance guaran teed. Lowest cost per year of use. Highest vacuum of any mechanical pump. Quietest me chanical pump made. When you buy a Duo-Seal Pump, you are buy ing a pump with a reputation. Over the years Duo-Seal pumps have built up this reputation for long-life dependability, quiet operation, long-term adherenee to original specifications.
Rigid design requirements make these pumps quiet operating, long wearing; meticulous fac tory inspection methods make sure that every pump is perfect when it leaves the plant. Triple Testing with McLeod gauges leaves no room for question on final performance.
For complete specifications, request our catalog.
The superior performance of DuoW . M. WELCH SCIENTIFIC COMPANY Seal Vacuum Pumps is due to the use of Duo-Seal Oil, a specially DIVISION OF W. M. WELCH MANUFACTURING COMPANY processed product that maintains t hese pumps at highest vacuum ESTABLISHED 1 8 8 0 and efficiency. Chemically stable, with low vapor pressure. Duo-Seal 1 5 1 5 Sedgwick St., Dept. A - 1 , Chicago 10, III., U.S.A. Oil meets the most rigorous lab oratory tests. Oil .75 qt. Manufacturers of Scientific Instruments and Laboratory Apparatus
H E V I - D U T Y "Multiple Unit" TUBE TYPE COMBUSTION FURNACES in Two Temperature Ranges, 1850° F. or 2200° F. Hevi-Duty Combustion Tube Fur naces are available in either the split* (illustrated) or solid type and can be used horizontally or modified for vertical operation. Long-life "Multiple Unit" brand heating units offer fast heat-up because the heat is radiated direct ly into the heating chamber. The heated length may be divided for zone t e m p e r a t u r e control which gives greater temperature uniform ity over a specified length. A few of the standard furnaces are shown below. Many sizes are in stock. Special sizes with diameters up to 16 inches can be built to your specifications :
5-in. and smaller rïiameîers are hinged. HINGED-TYPE TUBE FURNACE FOR 1 8 5 0 ° F. TYPE
CHAMBER DIA.
LENGTH 12"
RATING WATTS
SHIPPING WEIGHT
PRICE
70
1 % "
M-2012 M-3024
2%" 3"
24"
3400
135
t
250.00
M-5036
5"
34"
7500
325
$
650.00
M-8040
8"
40"
14500
520
$1180.00
12"
750
35
$
75.00
1400
90
$
165.00
Write for Bulletin 552 for complete details.
HEVI-DUTY A D I V I S I O N OF HEVI-DUTY
ELECTRIC
BASIC COMPANY,
Industrial Furnaces and Ovens. Electric and Fuel · Laboratory Furnaces ·
PRODUCTS MILWAUKEE
Dry Type Transformers
·
CORPORATION t. W I S C O N S I N Constant Current Regulators
Circle No. 47 on Readers' Service Card VOL
3 2 , N O . 7, JUNE 1 9 0 0 ·
75 A
