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and valuable work on the part of the Members of our body, truly 

 gratifying to all who have its welfare at heart. In the " Proceedings" 

 are two important papers on purely mathematical subjects, by Mr. 

 Young and by Professor Casey ; and in the " Transactions " Dr. Hart, 

 following Dr. Salmon, in reference to the theory of cubic curves, 

 communicates a paper of great value to the mathematician. Dr. 

 Doberck, of the Markree Observatory, describes the first comet of 

 1845, and at the request of Professor Bruhns of Leipzig, who is an 

 eminent authority in this department of astronomy, he undertakes 

 to determine the definite orbit of the comet. He also speaks of six 

 binary stars and a revolving double star. One of the most important 

 papers in the "Transactions" of 1875, which contains the substance 

 of communications read in 1860, 1863, and 1873, entitled "Researches 

 on Chemical Optics," is by our late distinguished President, who observes 

 that no part of the scientific field appears to promise more important 

 results to the investigator than the application of optics to chemistry. 

 "Optical science," observes Mr. Jellett, "has given to the chemist 

 the solution of problems whose very investigation seemed beyond 

 his reach. "Not only has the spectroscope conferred on him a power 

 of qualitative analysis far exceeding (where it is applicable) that 

 which he could derive from his own science, but it has also enabled 

 him to apply analysis to cases in which chemistry proper has been 

 hitherto, and probably would have remained, powerless. The 

 analysis of a nebula or of a planetary atmosphere, effected to a 

 considerable extent by the spectroscope, might seem to be beyond 

 the powers of ordinary chemical methods, while the phenomena of 

 rotatory polarization, if they are less striking, open a wide field for 

 chemical research, and most especially as regards the changes in the 

 rotation of the organic alkaloids by the addition of an acid." I shall 

 not attempt to follow Mr. Jellett through the mass of applied 

 mathematics and chemical research displayed by him in this great 

 and model paper. 



A valuable communication is given by Mr. Burton upon the faint 

 spectra of the zodiacal and auroral light, observed with the Academy's 

 spectroscope in the expedition to the island of Rodriguez. He 

 concludes that the zodiacal light is emitted by matter partly liquid, 

 partly solid, and mixed with gas. 



