282 



SCIENCE 



[N. S. Vol. L. No. 1290 



10 cm. per hour at the highest vacua. Hence 

 the air -within is permanently slightly hotter 

 than the outside, because of the influx. Fig. 

 7 shows the total excursions or double ampli- 

 tudes of the mass m, when the ball M is passed 

 from one side to the other of m^ in half hour 

 periods. The graph is a little rough because 

 the Ai/ for the plenum would not be quite con- 

 stant and the influx can not be perfectly con- 

 trolled in flow; but the evidence is none the 

 less definite. Conceding that the region be- 

 tween M and m is cold relatively to the other 

 side of m, there is always a radiant pressure 

 excess on the cold side of m, increasing nearly 

 at the same rate as the air pressure p de- 

 creases. In the high vacua the effect seems 

 even to be accentuated so that gravitational 

 attraction is all but wiped out. 



Nothing of the inversion so clearly brought 

 out by Figs. 3 to 6 appears in Fig. 7. In place 

 of it the plenum radiant pressure on the cold 

 side increases steadily, even into vanishing air 

 pressure, p, so far as observed 



If one computes the work done by the influx 

 of but 10 cm. per hour, so nearly isothermal, 

 as BiriT log (p'/p) in the usual notation (t 

 being absolute temperatiu'e), it is about the 

 same for all the points of Fig. 7. The case 

 therefore would always be heated alike, within. 

 On the other hand the temperature increment 

 A^ of the inside air, in the absence of all radi- 

 ation, may by an easy integration be found to 

 be Aff = (Er/Jk) log (p'/p) and this increases 

 as log (p'/p), about seven times between the 

 plenum and the high exhaustions;^ but it is 

 hard to discern how temperature, as such, not 

 considered as an index of the available heat, 

 has anything to do with it, unless there is 

 some other kind of radiation associated with 

 temi)erature. True, when temperature differ- 



1 The temperature increments of the inside air, 

 barring radiation, are 14° at p ^ 40 and about 

 100° at p ^ 7 em. What is effective, is the resi- 

 due, after one half hour's radiation, or more, of 

 this thin air. It seems incredible that such in- 

 finitessimals can leave so striking a record as fig- 

 ure 7. In fact, most of the straightforward ex- 

 planations which I have given for the sake of a 

 cohesive argument, if examined critically, are far 

 from satisfactory. 



ences decrease indefinitely, the times of cool- 

 ing must increase indefinitely; and the mean- 

 ing of infinity here depends on the delicacy of 

 the instrumentation. But the results thus far 

 do not show whether the temperature effect is 

 absolute or relative and I have not therefore 

 been able to get the mastery of the suspicion 

 that observation of the type of Figs. 1 and 2, 

 made under better conditions, daily, for a 

 period of years, would be worth while. 



Carl Bahus 

 Brown Universitt, 

 Providence, E. I. 



THE PHILADELPHIA MEETING OF THE 

 AMERICAN CHEMICAL SOCIETY 



The fifty-eighth meeting of the American Chem- 

 ical Society was held in Philadelphia, Pa., from 

 September 2 to 6,, 1919, inclusive, the general 

 meeting beginning on the morning of "Wednesday, 

 September 3, at the Bellevue-Stratford Hotel. 



Local arrangements had been under the clharge 

 of the committee headed by George D. Rosengar- 

 ten and members and guests were bountifully en- 

 tertained. One thousand six hundred and eighty- 

 seven members and guests registered for the meet- 

 ing. A considerable additional number of mem- 

 bers of the society came from the surrounding 

 cities and towns for special parts of the program 

 buit did not register. Fully 2,000 were in attend- 

 ance. 



An interesting innovation of the Philadelphia 

 Section consisted in the daily publication of the 

 Catalyst, wlhich is the official bulletin of the Phila- 

 delphia and Delaware Sections. This daily paper 

 contained news items, lists of members and guests, 

 the daily programs, reports of various meetings 

 and other entertaining matter. 



The general meeting opened with an address of 

 welcome by Honorable Joseph S. McLaughlin, of 

 the city of Pennsylvania, to which President 

 Nichols responded. A large audience completely 

 filling the Ball Room of the Bellevue-Stratford 

 Hotel, listened to the address by Honorable New- 

 ton D.' Baker, Secretary of War, on "Chemistry in 

 Warfare," and to an address on " Chemistry and 

 the Navy," by Bear Admiral Ralph Earle, chief, 

 Bureau of Ordnance, TJ. S. Navy. These addresses 

 will be found in the October number of the Journal 

 of Industrial and Engineering Chemistry, together 

 with additional details of the Philadelphia meet- 

 ing. 



