Notes and Memoranda. 161 



Production oe Diabetes by Cold. — The Proc Roy. Soc, No. 70, con- 

 tains a paper by Dr. Bence Jones, on the production of diabetes in rabbits by sur- 

 rounding them with ice, and thus arresting the processes of oxydation going on in 

 their bodies. The urine of rabbits naturally contains a little sugar, but the quan- 

 tity was notably augmented by exposing them to a low temperature. 



Invisible Radiation OE Electric Light. — Professor Tyndall describes the 

 distribution of the heat rays in the electric spectrum, in the Proc. Roy. Soc, No. 

 71. Melloni, Franz, Miiller, and others, found the heat to augment from the 

 "violet to the red, while the maximum effect was beyond the red, and at a distance 

 from the red, in one direction, equal to that of the green of the spectrum in the 

 other. The augmentation of temperature beyond the red is sudden and enormous. 

 If the amount of heat in different parts of the spectrum is indicated by a curve 

 following its increase or decrease, a steep peak must be described beyond the red, 

 aud this peak is much steeper and more abrupt in the electric than in the solar 

 spectrum. Professor Tyndall supposes that the aqueous vapour in our atmos- 

 phere has toned down the solar rays. A solution of iodine in bisulphide of car- 

 bon stops all the light rays, and allow the heat rays to pass freely. Professor 

 Tyndall converges the rays of an electric lamp by a concave mirror, stops the 

 light by a screen of the iodine solution, and ignites wood, lights cigars, etc., in the 

 dark focus of the non-luminous rays. 



Nature oe Sun Spots. — Messrs. De la Eue, Balfour, Stewart, and Benj. 

 Loewy, have communicated to the Royal Society (see Proc, No. 71) the results of 

 numerous observations on solar spots. The majority confirm the belief that the 

 umbra of a spot is at a lower level, or nearer the crater than the penumbra. 

 The faculas, or light-streaks, appear to be above the spots at a high elevation in 

 the solar atmosphere. The bottom of the spots is supposed to be of a lower 

 temperature than the photosphere, and this luminous photosphere is considered not 

 to be composed of solid or fluid mattter," but rather of the nature of a gas or cloud." 

 Observations of a sun spot, by Professor Phillips, of which details will be found in 

 same publication, detected perspective appearances, which showed that it was, on 

 a whole, not sunk very much below, or raised very much above, the general level 

 of the region. He thinks the black nuclei of spots the sun's body ; the penumbra 

 that body partially seen through the atmosphere. The faculse, he supposes, trans- 

 mit rays which have acquired a higher refrangibility than that with which they 

 started. 



Mr. Huggins on the Orion Nebula. — In Mr. Burr's article on Celestial 

 Chemistry, it was Btated that Mr. Huggins had obtained a gaseous spectrum from 

 the Great Nebula in Orion. Since then a paper on the subject appeared in the 

 Proc Roy. Soc, No. VI, containing some fresh particulars. Nebulas 4760, 4678, 

 in Sir J. Herschel's catalogue, which are " well resolved " by telescopic power, 

 give continuous spectra, indicating their difference from other nebulae, which give 

 only certain lines of light, indicating that they are gases producing rays of one 

 degree of refrangibility. When the Orion nebula was examined, the light from the 

 brightest part near the trapezium was resolved by ODe prism into three bright 

 lines, in all respects similar to those of the gaseous nebulas described in our 

 January number. When the stars of the trapezium were brought upon the slit, 

 continuous spectra were obtained. The whole of the nebula that was bright 

 enough to be examined, gave the same spectrum of three bright lines only. Thus 

 the detection by large telescopes, in this or other nebula, of an assemblage of 

 minute points of light, can no longer be accepted as proof that the object consists 

 of truestars. Mr. Huggins remarks, "it is worthy of consideration that all the 

 nebulas which present a gaseous spectrum, exhibit the same three bright lines ; 

 in one case only, 18 H. IV., was a fourth line seen." Mr. Huggins' theoretical 

 suggestions are, we think, open to some objection. He says, if we suppose the 

 gaseous substance of nebulas, the nebulous matter which, by condensation, fprms 

 stars, " we should expect a gaseous spectrum, in which the groups of bright lines 

 were as numerous as the dark lines due to absorption, which are found in the 

 spectra of stars." Are we not equally entitled to say we should not expect 

 anything of the kind? If the nebulous theory of star formation be accepted, we 



