434 SCIENTIFIC RECORD FOR 18S2. 



W. S. Jevons, after describing the five auroras of August as seen bj 

 him in Korway, adds: After thinking the matter over for three months, 

 and comparing the auroral coruscations above described with the ex- 

 quisite discoveries of Mr. Crookes, taking into account also some remarks 

 in the article on auroras in the new edition of the"Encyclopsedia Bri- 

 tannica," I venture to make the suggestion that these coruscations arise 

 from highly tenuous matter (in what Mr. Crookes calls the radiant state] 

 projected through the higher part of the atmosphere. It is not possible 

 in words to give an impression of such a phenomenon in the least degree 

 approaching to that naturally acquired by watching it under favorable 

 circumstances for several hours. My belief is that, during the auroras 

 described, i)J/#«, as it were, of radiant matter were discharged at a great 

 elevation above the earth's surface, and the luminosity of these putts 

 l)erhaps arises from conflicts between the projected molecules and those 

 already spread about the almost vacuous space. The arch and most of 

 the streamers probably belong to a lower, though still a very high part 

 of the earth's atmosphere ; but certain of the streamers, as well as 

 patches of luminous matter seen on the night of the 13th, certainly ex- 

 ist in the lofty regions through which the radiant matter is projected. 

 The explanation of the streamers must probably be approached through 

 that of the coruscations, but they are efiects of a very different kind. 

 {Nature, December 16, 18S0, xxiii, p. 149.) 



Prof. W. G. Adams, in a suggestive lecture on magnetic disturbances, 

 auroras, and earth currents, is almost entirely confined to the results of 

 British work. With regard to the aurora he seems to teach that its ul- 

 timate cause must lie in the changes of the sun's magnetism, and in 

 tides of the oceans of air above us. The existence of such aerial tides, 

 due to the attraction of the sun and moon, has never been recognized 

 by meteorologists, and it would seem necessary for Professor Adams to 

 establish this hypothesis on a firmer foundation. {Nature, xxv, pp. 

 65-71.) 



Dr. Spottiswoode, at the conclusion of one of his brilliant lectures on 

 matter and magneto-electric actions, concludes as follows : " We may even 

 carry the suggestion of a resistance of the second kind a little further, and 

 supijose that there is a resistance due to the passage of electricity from 

 a medium of one density to another, or from layer to layer, of different 

 degrees of pressure. And from this point of view we may regard the 

 striae as expressions of resistance due to the varying pressure in differ- 

 ent parts of the tube. Into the question, whence this variation of press- 

 ure, I am not, at present, prepared to enter; it must suffice for this even- 

 ing to have shown that the conclusions which we have drawn from our 

 experiments are not in disaccordance with other known phenomena of 

 the electrical discharge. 



" Before closing I would point out that these laboratory experiments 

 are not unsuggestive in reference to larger questions. It has long been, 

 and still is, a disputed question whether a display of the aurora borealis 



