Back MatterSource: The Scientific Monthly, Vol. 61, No. 5 (Nov., 1945)Published by: American Association for the Advancement of ScienceStable URL: http://www.jstor.org/stable/18571 .

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IMPRO0VED Eastman Spectroscopic Plates

Type I THE Type I emulsion for Eastman Spectroscopic Plates

with Class 0, J, H, G, T, D, B, C, and F sensitizings has recently been improved. The new Type I plates have greatly increased sensitivity and slightly lower contrast compared with previous plates, with approximately the same granularity.

By way of example, SA speeds* are shown in the following table for the new Type I-0 and I-F Spectroscopic Plates in comparison with previous coatings of these plates. The values given in the table are on the same basis as the values published in Table I of the booklet Photographic Plates for Use in Spec- troscopy and Astronomy (5th Edition, 1943).

Spectroscopic Astronomical Exposure Exposure

Plate 1 sec. 1e4 sec. Gamma

I-0 55 11 2.00 New 1-0 76 15 1.38

I-F 44 2 1.50 New I-F 87 13 1.10

*SA =/E, where E =exposure in rn.c.s. of light of sunlight quality required to pro- duce a density of .60 above fog when developed to the specified gamma in Kodak Developer D-19.

The effective speed of the new Type I emulsion increases with development time, the limiting factor being the back- ground fog.

EASTMAN KODAK COMPANY

Researecl Laboratories ItoelIenter 4, N. Y.

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FLYING ANTENNAS l Television and FM programs will be beamed (solid tines) from / a ground stations and from plane to plane (dotted lines) ... for rebroadcast to shaded areas 14 Stratovision planes, now being developed by Glenn L. Martin Company can cover 78%I of the nation s population. \

How WoVestinghouse STRATOVISION took the final headache out of Television and FM

Nbefore the war ended, broadcasting Television and mately $400,000 000 worth of Televisio and FM trans- FM programs from planes Radar and radio equipment

mitting and receiving equip flying six miles high in the for our armed forces ment had reached a high stratosphere! degree of perfection But a At this altitude, a single programs. final difficulty remained the Stratovision plane can covei problem of broadcasting pro- an area 422 miles in diameter grams on a nationwide basis. 103,000 square miles..

Bcauseserioustdistorton-ofigh ...

Becase f te ulra igh approximately the combined /~'> frequencies employed, Tele- area of New York, New Jer- vision and FM waves travel sey and Pennsylvania only in straight, lineof Westinghouse engineers sight" direction. They do not predict that 14 of these fly- bend around the earth's sur ing broadcasting stations can face ... as do those of stand- transmit 4 Television and 5 ard-band radio. FM programs simultaneously

This limits the range of a to 78 % of the nation' p opu-HR H ERT Srtvso Televisio or FM sttion to alation. broadcasting, serving an area of 103,000 maximum of 50 miles even The conception and plan- square miles, will require only 1/50th

buildng pece tptetletning of Stratovision broad- as much power as a 50 kilowatt ground chain ofradio reay sta Fasting are a tribute to the transmitter covering only 7,900 square A chainof radi-relay ta- inenuity nd engieeringmiles. That's why a single Sfrafovision

t'ions across the country -or ikngenuity and Wengineering plane can easily carry and power the coaxial cables spanning the ko o fWsigos equipment needed for simultaneously

nation have een proposed radio technicians ..gained transmitting 4 Television and 5 FM nastaiolution butn thepsedar through producing approxi- programs. terrifically expensive and cause serious distortion of ~T long-distance programs. v estrilouse, Now, at last, Westinghouse 2ciis OFcsERYH*

research engineers have dis- (JNSI 5CilS *FCS VRWO

covered a practical solution Tune in JH HRE HMSSna 3 m 5 B through "STRATOVISION TED MALONE -Monday through Friday, 11:45 am, EST, Amnerican Network

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