226 Inielligence and Miscellaneous Articles. 



assumed or solar irradiation, Dr. R. was led to conjecture that ilie 

 lunar irradiation may be obtained, generally, by multiplying tlie solar 

 irradiation by 1*7 *. 



In 1S27 the new transit was put up at Armagh, and the solar irra- 

 diation was found, by seventy-four observations, to be +0%0l com- 

 pared with Greenwich, and +0%19 with Dublin, through the data 

 of the Nautiml Almanac; whence the comparative lunar irradiations 

 would be respectively +0%02 and -|-0%32, on the preceding hypo- 

 thesis. With this correction, the longitude of Armagh was found 

 to be m s 



by 10 corresponding observations 1) \ L Armagh and Dublin 26 30,49 W. 

 5 • 1) 2 L i;6 30,34 \V. 



Mean. ,.26 30,40 

 which must be very near the truth. 



by 6 corresponding observations at Armagh and Greenwich 26 29,89 



but with a much greater probable error. 



It would appear, therefore, that this mode of obtaining the com- 

 parative lunar irradiation applies to the; new transit as well as to 

 the oldf. 



All the results have been obtained by the method of minimum 

 squares, and the probable errors are also given 



The formula is stated, by which the longitude is deduced from the 

 observations, with a type of the calculation. 



M 



XXXIII. Intellige7ice and Miscellaneous Articles. 



ELECTRICAL FORMATION OF CRYSTALLIZED SULPIIURET. 



ANY chemical compounds which occur in the bowels of the 



earth, may also be produced in the laboratory ; and there are 

 some others which may also be obtained artificially, but not crystal- 

 lized as they'occur in nature. 



M. Becquerel has attempted to supply the deficiency which existed 

 in this branch of science, and to furnish geology with the requisite 

 facts to explain their formation. It results from his labours, that 

 what was required in the apparatus of chemists to enable them to 

 emulate the products of nature, was the influence of electric forces 

 acting with slight tension and in a continued manner. 



• This greater irradiation of the moon may be owing to her greater bril- 

 liance, and to the sympathy excited in the adjacent portions of the retina. 

 Dr. R. finds that the lunar irradiation is much less in the daj-time. During 

 the winter months, the dark limb of the moon might probably be observed 

 with powerful telescopes, and the irradiation determined. 



t Old transit of Armagh 3 ft. focal length, 2 in. aperture, partly covered by 



an illuminator. 



New ^— 5 ■ 3J ■ limited for sun 



and moon to 2 J. 



Greenwich transit... 10 5 



Dublin transit 6 • 4 of which 2| only 



are used. 



In 



