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1975 GAS CATADG
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Matheson's 1975 Gas Catalog brings together all you need to know about specialty gases, equipment, mixtures, safety items and procedures, cylinders and markings, physical data and much, much more. Best of all, it's yours for the asking. Just fill in the coupon below and send it t o us. You'll be glad you did. Fdarne
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Company Address City zip
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Tel. (-)
M A T H E S O N GAS PRODUCTS P 0 . Box 85, 932 Paterson Plank Road, East Rutherford, N I 07073
MEETS ALL E.P.A. SPECIFICATIONS
Chemtluminescence principle Compact completely self contained Atmospheric pressure operailon Analysis by unattended Operation Rapid response M o d e l 1200 A Ranges 0-02 0 5 1 0 8 2 0 p p m M o d e l 1400 Seven Ranges '-loo p p t o O - l 0 Oo0 ppm 1500 NO-NO2 Callbratlon Gas Source provides sus'ained calibrated stable gas source May be set from 0 2 to 1 000 p p m
Series 1110 Chemiluminescence principle Ranges 0.1 0 P p m to 1 % concentrations Series 1100 Ranges 0-05 0 1 0 5 1 0 5 0 100 PPm
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1000 Ozone Generator provides sustained highly repealable stream of ozonized air from i o p p b to i o p p m
NEW! 12 LB? PORTABLE AC/DC MODELS Chemiluminescence principle Full recorder outpu' capablllty M o d e l 2000 Ozone Meler Ranges 0-01 0 2 0 5 1 0 p p m M o d e l 2100 NO NO2 NOx Meter Ranges 0-5 10 20 50 p p m
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Internal 10 lb battery pack optional
M o d e l 2200 NO'NO2 NOx Meter Ranges 0 0 5 1 0 2 0 5 0 p p m
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CIRCLE 6 ON READER SERVICE CARD
CIRCLE 3 ON READER SERVICE CARD
LETTERS Solar energy Dear Sir: Your November article (ES&T, Nov. 1974, p 976) was very interesting but neglected to mention that, as usual with energy sources, in very special cases solar energy can be available at amazingly low cost and in fact at lower cost than atomic energy. In the St. Clair Solar Energy System a large number of mirrors reflect sunlight on a pile of pebbles, or rather pebbles covered with a lattice brick work, which can be covered by an insulated door when the sun is not shining. When the sun is shining the large numbers of mirrors heat up the surfaces of the lattice brick work and the surface of the pile of pebbles to over 2000°F. My years of experience with pebble beds in heat exchange have shown m e that if you rapidly suck air into the pile of pebbles the heat that hits the surface of the pile of pebbles, can be drawn into the center of the pile of pebbles. Since in special cases the cost of the pebbles is less than 25a: per ton and you have a heat 4
Environmental Science & Technology
Radioactivity from Pu
storage cycle of from 120OoF to over 2000°F the cost of storing the heat of the sun for as much as a year is very low cost. You find the major cost of such a solar heat process in the mirrors. In this way solar heat becomes very dependable and you do not have to put in the large excess of solar heat collectors, as necessary with other processes, in order to get a reasonable amount of solar heat during the winter months when the solar heat collectable is only a fraction of that collectable in the summer. And besides requiring such a lower area of collectors (mirrors) the solar collectors used are so much cheaper per square foot than the ones described in your article. l have gotten from RANN project workers the cost of mirrors made of metallized plastic film held like drum heads over hoops, and with their rotating mounts cost about $2 a square foot with a good chance of reducing the cost of the mirrors to $1 per square foot. This checks with my own estimates.
Dear Sir: In the Currents section ( € S A T . July 1974, pp 597-8) the short article, "Ohio's Erie Canal , . ." is written in an extremely inflammatory manner. Certainly plutonium is poisonous but other metals, such as platinum, mercury, etc., are also. Why use the inflammatory adjective "man-made poisonous" when referring to plutonium? Also the sentence, "Plutonium can cause instant death only if inhaled," is certainly inflammatory and probably not true. Plutonium has been inhaled on several occasions (Health Phys., 25 ( 5 ) , November 1973, p 461) and "instant death" or even delayed death has not resulted. Objectivity is desperately needed by all those reporting on technology today. Certainly an ACS journal should be foremost in objective reporting.
John C. St. Clair London, Ohio 43140
Kansas State University Manhattan, Kan. 66502
N. Dean Eckhoff
