dl:4 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



that the chemically active rays at the center hav^e from three to five times 

 the intensity of those at the edge. This difiereuce, being- greater than the 

 difference in heat from the same portions, is accounted for by the greater 

 absorption effected b}^ the solar atmosphere on the more refrangible rays. 

 It also appeared that the chemical brightness of the south polar regions 

 was considerubly greater than that of the north polar region, while about 

 the equator the brightness was between that of the poles. Mr. Eoscoe, in 

 connection with Mr. Baxendell, proposes to carry out, upon the same meth- 

 ods a series of observations relative to the amount of chemical brightness 

 of the sun's disc, and hopes before long to furnish further details to the 

 Society. 



Indium. 



Prof. Eoscoe, in his lecture before the Royal Institution, London, on the 

 6th of May, said the new metal, indium, is distinguished by two splendid 

 indigo-blue lines in its spectrum. In its chemical relations it resembles 

 zinc. It was first found in the Freiberg zincblende. It can be reduced by 

 the blowpipe to a malleable bead. It is detected in its compounds by the 

 deep purple it imparts to the flames. 



New Use of the Spectroscope. 



Prof. Roscoe alluded in the same lecture to the remarkable application o f 

 the spectroscope to the exact and very important moment when the blowing 

 of cold air into the molten iron should cease in the Bessamer process, by 

 which, in about fifteen minutes, the iron is said to be converted into steel. 

 In relation to this item, Prof. Joy remarked that in Europe, the workmen 

 having charge of the furnace department of the steel mannfactories are 

 very expert in determining the proper length of exposure to heat; they 

 have a quick eye for distinguishing the peculiar color of the flame required 

 for making good iron. This art is only acquired after long practice. With 

 the spectroscope, sulphur and all other substances which would render the 

 steel impure would be readily detectc^d by the characteristic color belong- 

 ing to each. 



Dr. Howell inquired whether the lines of color could all be distinguished 

 at once. 



Prof. Joy replied that this would depend on the number of prisms era- 

 ployed, and the time in which they were turned. 



Production of Monsters. 



M. Barthelemy has been experimenting on artificial and natural mon- 

 strosities among the butterfly and moth order of insects. He endeavored 

 to cause modifications in the chrysalis similar to those obtained by cover- 

 ing the eggs of birds with varnish. The use of oil was fatal, but on cover- 

 ing the head, throat, and abdomen with wax. the development of these 

 parts was much retarded. The nervous system of other portions seemed 

 to be developed as usual, yet the power of reproduction was destroyed. 



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