INDUSTRIAL PROGRESS DURING THE YEAR 1873. xxxv 



having for its period twenty-six days, and therefore pointing 

 toward the solar diurnal revolution rather than to the solar 

 spots as its origin. 



In the study of auroras, we notice that the review, by Donati, 

 of Florence, of the phenomena attending the aurora of Feb- 

 ruary 4, 1872, has called forth encomiums from observers in 

 all parts of the globe. On the other hand, the extensive ta- 

 bles of Professor Lovering, of Cambridge,Massachusetts, have 

 enabled Professor Loomis to review and extend his investi- 

 gations into the periodicity of the auroral phenomena, and to 

 establish with great probability some of the details of the 

 connection between solar spots and auroral phenomena. 



ELECTRICITY. 



In Electrical Science, one of the most important steps taken 

 has been the founding, in 1872, of the new society of tele- 

 graph engineers in London, from wdiose proceedings numerous 

 extracts will be found in our pages. 



An excellent memoir on electrical dissipation, by Bobou- 

 lieff, has appeared in the Journal of the St. Petersburg soci- 

 eties of physics and chemistry ; and in the same city has been 

 successfully tried the new method of electric illumination, 

 by Ladiguin, which, in connection with the newly invented 

 magneto-electric machine of Gramme, promises to fully real- 

 ize the long-deferred expectations of the advocates of this 

 method of illumination. The curious effect of light in increas- 

 ing the electrical resistance of a bar of selenium has been 

 quantitatively investigated by Lieutenant Sale, R. E., and has 

 been proposed as the basis of a new photometer. The allied 

 action of heat has been extensively studied by Benoist for high 

 temperatures. The intimate theoretical connection between 

 these phenomena promises at no distant day to lead to more 

 satisfactory views of the true nature of the electric force. 



The theory of Edlund as to the nature of electricity has 

 been mathematically developed by himself and others, show- 

 ing a remarkable agreement with observations. On the other 

 hand, the profound work of Maxwell has, with equal success, 

 developed what may be called the vibratory theory. The 

 genernl dissemination of the results of the studies of the past 

 thirty years has been greatly facilitated by the publication 

 of the admirable works of Thomson, Jenkin, and Maxwell. 



