478 



SCIENCE 



[N. S. Vol. XXIX. No. 742 



These records tell us, among other things : 

 (a.) That through the first ten thousand feet 

 next the earth the temperature changes irregu- 

 larly, and often has one or more layers warmer 

 than the regions immediately below or above them. 

 (6) That roughly between ten thousand and 

 forty thousand feet above the surface of the earth 

 the temperature falls tolerably regularly, ap- 

 proximately at the rate of 0°.7 C. per hundred 

 meters, or 0''.4 F. per hundred feet. 



(c) That somewhere in the neighborhood of 

 forty thousand feet elevation the temperature 

 quits falling, usually abruptly, and commonly 

 increases slowly from this level up to the greatest 

 elevation yet reached, about 26.6 kilometers (16* 

 miles). 



The place where the temperature quits falling 

 and begins to rise is called the inversion level. 

 Its elevation and its temperature both change 

 with seasons, with latitude, and with storm con- 

 ditions. 



This inversion and all the other phenomena 

 connected with the temperature gradients of the 

 atmosphere appear to be satisfactorily accounted 

 for by the known composition of the atmosphere 

 and the laws of radiation and absorption. 



The paper in full appears in the Astrophysical 

 Journal, January, 1909. 



Some Results in Solar Magnetism: W. J. Hum- 

 phreys, Mt. Weather Observatory, Md. 

 The splendid work of Hale and others at Mount 

 Wilson has led to the conclusions: (a) that sun 

 spots are cooler than the surrounding regions; 

 (6) that they are centers of violent cyclones; 

 (c) that they are accompanied by mag-netic fields 

 of great intensity. 



Assuming the effective temperature of the sun 

 to be 6,000° C, simple convection can reduce the 

 temperature of solar vapor to about 5,000° C, 

 so that lower temperatures, if such exist, must 

 be due to some such explosive action as Fox has 

 shown to accompany the spots. 



The observed tangential velocity of 100 kilo- 

 meters per second can not be accounted for as 

 the result of simple differences in barometric 

 gradients. 



The observed magnetic field can not be due to a 

 whirling surface charge, since a charge sufficient 

 to produce it would cause disruptive radial forces. 

 A volume charge, however, of the negative sign, 

 analogous to that which somehow exists in the 

 earth's atmosphere might lead to the observed 

 effects. 



The magnetic fields of the sun spots, however 

 produced, can not extend in measurable amounts 

 to the earth, and therefore our magnetic storms 

 are still without a definitely assignable cause. 



The full paper appears in Terrestrial Magnetism 

 amd Atmospheric Electricity, December, 1908. 

 Note on Thermoluminescence : Elizabeth R. 

 Laibd, Mt. Holyoke College. 

 Theory suggests that the change producing 

 luminescence goes on very slowly at ordinary 

 temperatures in thermoluminescent salts and is 

 merely accelerated by raising the temperature. 

 An additive method of obtaining the effect of 

 thermoluminescence should therefore show its ex- 

 istence at room temperatures. 



This was tested by wrapping up photographic 

 plates for different periods of time with sensitive 

 film toward a thermoluminescent salt and devel- 

 oping later, at the same time heating the salt to 

 observe the remaining effect. 



The salts used were solid salt solution of cal- 

 cium sulphate and magnesium sulphate, the same 

 with an undetermined admixture and calcium 

 sulphide which had been kept in the dark some 

 time after all visible luminescence had ceased. 



The results showed that the photographic plate 

 was unaffected in each case, with exposures vary- 

 ing from two weeks to two months, according to 

 the salt used and the amount of its previous ex- 

 posure to light. Where the effect was uneven the 

 greater effect corresponded to the portions showing 

 brighter thermoluminescence. Control plates used 

 with salt that had not been exposed to light after 

 heating showed no effect in the same time. 



These experiments indicate that there is a slow 

 change in thermoluminescent salts, probably sim- 

 ilar to that occurring at a higher temperature. 



Alfbed D. Cole, 



Seo'etary 



THE AMERICAN PHYSIOLOGICAL SOCIETY 

 The American Physiological Society met in the 

 physiological laboratory of the Johns Hopkins 

 University, December 28 to 31. Sessions for the 

 reading of papers were held in the forenoons of 

 December 29, 30, 31 and the afternoon of December 

 31. Demonstrations were given in the afternoon. 

 Seventy papers and demonstrations were presented. 

 A joint session with the American Society of 

 Biological Chemists was held December 29. On 

 the afternoon of the twenty-ninth the society met 

 with Section K to hear the address of the retiring 



