64 Notices respecting New Books. 



hitherto masked properties now under investigation come into 

 play. 



Rays of Molecular Light. — In speaking of a ray of molecular 

 light the author has been guided more by a desire for conciseness 

 of expression than by a wish to advance a novel theory. But he 

 believes that the comparison, under these special circumstances, is 

 strictly correct, and that he is as well entitled to speak of a ray of 

 molecular or emissive light when its presence is detected only by 

 the light evolved when it falls on a suitable screen, as he is to speak 

 of a sunbeam in a darkened room as a ray of vibratory or ordinary 

 light when its presence is to be seen only by interposing an opaque 

 body in its path. In each case the invisible line of force is spoken 

 of as a ray of light ; and if custom has sanctioned this as applied 

 to the undulatory theory, it cannot be wrong to apply the expres- 

 sion to emissive light. The term emissive light must, however, be 

 restricted to the rays between the negative pole and the luminous 

 screen ; the light by which the eye then sees the screen is, of 

 course, undulatory. 



The phenomena in these exhausted tubes reveal to physical 

 science a new world — a world where matter exists in a fourth 

 state, where the corpuscular theory of light holds good, and where 

 light does not always move in a straight line — but where we can 

 never enter, and in which we must be content to observe and ex- 

 periment from the outside. 



VIII. Notices respecting New Boohs. 



I. Report on the Administration of the Meteorological Department of 

 the Government of India in 1876—77. 



II. Report on the Meteorology of India in 1876. By Henry F. 

 Blajsteord, Meteorological Reporter to the Government of India. 

 Second Tear. Calcutta, 1878. 



III. Indian Meteorological Memoirs. Published by order of His 

 Excellency the Viceroy and Governor General of India in Council, 

 under the Direction of Henry F. Blajntord, Meteorological Re- 

 porter to the Government of India. Calcutta, 1878. 



rPHESE publications make us acquainted with the progress of me- 

 -*- teorological work in India during the year 1876, under the able 

 superintendence of Mr. Blanford. From them we learn that the 

 system of Meteorological Observation, the administration of which 

 was concentrated by order of the G-overnment in a single central 

 office, has not only worked well, but that the area over which it 

 now extends embraces 43° 30' of longitude and 24° of latitude ; viz. 

 from 51° to 94° 30' of east longitude, and from 10° to 34° of north 

 latitude. 



For many years the pursuit of meteorology consisted in obser- 

 ving the indications of the instruments at certain periods of the 

 day, and deducing from the readings thus obtained the mean tem- 

 perature or pressure at these periods ; but of late years a much 



