188 



SCIENCE 



[N. S. Vol. XLIX. No. 1260 



through the cycle of union (facilitated by any 

 charges they may carry) and division, of co- 

 alescence and disruption, from one to many 

 times, with the formation on each at every 

 disruption again according to experiment, of 

 a corres]>ondingly increased electrical charge. 

 The turmoil compels mechanical contact be- 

 tween the drops, vrhereupon the disruptive 

 equalization of their electrical jwtentials 

 breaks down their surface tensions and in- 

 sures coalescence. Hence, once started, the 

 electricity of a thunderstorm rapidly grows to 

 a considerable maximum. 



After a time the larger drops reach, here 

 and there, places below which the updraft is 

 small — the air can not be rushing up every- 

 where — and then fall as positively charged 

 rain, because of the processes just explained. 

 The negative electrons, in the meantime, are 

 carried up into the higher portions of the 

 cumulus, where they miite with the cloud 

 particles and thereby facilitate their coales- 

 cence into negatively charged drops. Hence 

 the heavy rain of a thunderstorm should be 

 positively charged, as it almost always is, and 

 the gentler portions negatively charged, which 

 also very frequently is the case. 



Such in brief is Dr. Simpson's theory of the 

 origin of the electricity in thunderstorms, a 

 theory that fully accounts for the facts of ob- 

 servation and in turn is itself abundantly 

 supported by laboratory tests and imitative 

 experiments. 



The foregoing are only a selected few of 

 the many recent contributions to the physics 

 of the air, but they are sufficient, it is hoped, 

 to show that meteorology is indeed a progres- 

 sive branch of physics, and one eminently 

 suitable to every type of scientific talent. The 

 close observer, the clever experimentalist, and 

 the keen analyst all can find in the phenomena 

 of the atmosphere inexhaustible material and 

 endless opportunities. But in science op- 

 portunity is only a synonym for duty, and of 

 all words duty is the noblest. 



W. J. Humphreys 

 TJ. S. "Weathee Bukeau 



SCIENTIFIC EVENTS 



THE HISTORY OF MEDIEVAL INSTITUTIONS 



Professor David Eugene Smith, of Teach- 

 ers College, Columbia University, writes: 



The Societfi de Seolastique Medi(5vale, founded 

 by M. Francois Picavet, professor in and secretary 

 of the College de France, was changed into the 

 Societe d' Histoire Ggn^rale at Comparee des Phi- 

 losophies Medigvales in 1906. This society is in- 

 terested in the study of the history of dogma and 

 religion, the history of law, the history of letters, 

 the history of philosophy, and the history of 

 science. Monographs have been issued in all these 

 several lines and others are in the course of prepa- 

 ration. 



It may seem that this is not an opportune mo- 

 ment for scholars to be considering such a line of 

 work. Upon this point a letter from M. Picavet, 

 written just before the armistice, has this to say: 

 "En ce moment ou nous ne pouvons, en raison de 

 notre age, que faire des voeus, pour les combat- 

 tants ou venir en aide aux prisonniers, aux soldats 

 et aux 6vacu6s des pays envahis, j 'ai pens6 que 

 nous pourrions nous rendre utiles en preparant les 

 moyens de nous suffire sur le terrain soientifique et 

 universitaire, entre nous gens de 1 'entente et amis 

 de 1 'entente. " 



Few scholars have been called upon to make a 

 greater sacrifice in this war than M. Picavet, and 

 his determination to continue his great work in the 

 field in which he has done so much will doubtless 

 appeal to all scholars in this country as in Europe. 



M. Picavet would be glad to hear from Ameri- 

 can scholars who are interested in the work of 

 the society and to have their names enrolled as 

 sympathetic with its work. If they should later 

 become so interested as to contribute in any way 

 to the support of the society, this would be a wel- 

 come decision; but this is not the immediate pur- 

 pose. It would be a helpful act if those interested 

 in this line of work were to write to M. Francois 

 Picavet, College de France, Paris, expressing their 

 interest in the society. 



If America could in some way secure an endow- 

 ment of $24,000 for maintaining for ten years the 

 chair which M. Picavet fills with such distinction 

 in the College de France, a great impetus would 

 thereby be given to this work. 



ACTIVITY OF KILAUEA VOLCANO 



Peopessor Vaughan MacCaughey, of the 

 College of Hawaii, Honolulu, writes under 

 date of January 22: 



