INDUSTRIAL PROGRESS DURING THE YEAR 1876. xxi 



cupiecl with the development of his new views on the theory. Schjel- 

 lerup has also given the subject some attention, his only published 

 work being, however, a reply to StockwelFs pamphlet. A new lunar 

 inequality has been detected by Newcomb. 



Lohrmann's map of the moon is now to be completely pub- 

 lished under the editorship of Schmidt, who is also publishing 

 his own great chart. Tempel is likewise engaged on a map of 

 the moon. 



Neison has embodied his work on the moon's atmosphere, phys- 

 ical features, etc., into an octavo book lately published. 



Work on the British Association chart of the moon (Birt's) is, we 

 believe, temporarily suspended for want of funds. 



It is understood that the attraction-meter devised by Dr. C. W. 

 Siemens, and exhibited by him at South Kensington, is soon to be 

 applied by Sir William Thompson to determine the mass of the 

 moon. 



THE PLANETS AND SATELLITES. 



Drawings of Mars continue to be made by Terby and others. 

 Trouvelot, of Cambridge, has made one hundred and twenty-five 

 drawings of Jupiter during the present opijosition a very impor- 

 tant work, as the planet was too low for observation in Europe. 

 Trouvelot confirms the statement of Lohse that changes of unusual 

 magnitude are this year occurring on Jupiter. He also has pub- 

 lished a drawing of Saturp, with a discussion of its physical features, 

 in which some new views of the shape of the rings are advocated. 

 Weber's supposed observation of Vulcan, on April 4th, 1876, has led, 

 by request of Le Verrier, to a general examination of the sun, on 

 October 2d and 3d, and 9th and 10th, with the object of detecting 

 this planet in transit. This search was unsuccessful. 



Janssen has devised an apparatus by means of which a photograph 

 of the sun may be automatically taken every quarter of an hour, and 

 this he proposes to erect at Paris, for the purpose of detecting inte- 

 rior planets in transit. The whole question of the existence of a 

 jDlanet interior to Mercuiy (Vulcan) has been carefully examined in 

 a series of memoirs by Le Verrier, abstracts of which are given in 

 the following pages. His general conclusion is that in 1885 a 

 transit of Vulcan will take place, and to that time he defers the defi- 

 nite answer to the question of Vulcan's existence. 



It has been pointed out, however, that in 1878 a very favorable 

 total solar eclipse occurs in America, and with proper care such a 

 body as Vulcan is supposed to be can hardly escape detection if es- 

 pecial attention is directed to it. 



