Notes and Memoranda. 48 1 



that a body falling into the snn at a velocity of 390 miles a second, 

 would attain a temperature 9000 times that produced by the com- 

 bustion of coal. A body the size of the earth falling into the sun 

 would supply its heat for about one hundred years, but would make 

 no appreciable increase in its bulk ; and were the earth's motion 

 suddenly arrested, the heat developed would raise the temperature 

 to such a degree that the elements would be dissipated in vapour. 

 Notwithstanding the difficulties in the way of receiving this theory 

 of Dr. Mayer's, it was regarded by Dr. Tyndall as that which offered, 

 the best explanation of the cause of solar heat. 



NOTES AND MEMORANDA. 



Diffusion of Eubiditth. — M. Grandeau discovers this newly-recognized 

 metal in coffee, tea, tobacco, grapes, and crude tartar. The tobacco employed 

 came from Kentucky and Havannah. The leaves were acted upon by water, which 

 was evaporated, and the residue calcined and tested by the method of spectrum 

 analysis, which indicated potassium, a small quantity of lithium, and a notable 

 proportion of rubidium. Coffee is still richer in rubidium than tobacco ; but, as 

 is the case with tea, yields no trace of lithium. He found no rubidium in colza, 

 cocoa, and cane sugar, nor in certain kinds of fucus. 



Distribution" of Springs. — The Abbe Eichard, Professor at the little school 

 of Montlieu, announces his discovery of what he calls a " hydrogeologic" law, by 

 which he professes to be able to tell, after a brief examination of the soil, the 

 position and depth, together with the volume of the water to be found below. He 

 give3 numerous instances of successful predictions, but states that before explaining 

 his method he wishes to verify it by further experiments. 



Experiments on Solubility. — M. Gay-Lussac has ascertained that the 

 " solubility of a body is not modified when it passes from the solid to the liquid 

 state." The converse of this proposition is also affirmed, that is to say, " that the 

 presence of a solvent does not modify the fusing temperature of a body if no 

 chemical action takes place." Thus, if finely-divided sulphur is suspended in sul- 

 phuric acid, bichloride of tin, and amylic alcohol, which are three of its solvents, 

 it is seen to enter into fusion (be dissolved) in the three liquids exactly at the 

 same temperature of lll 0- 5 Cent. Phosphorus enters into fusion at 44° Cent, in 

 water, the various alcohols, chloroform, bichloride of tin, etc. Similar observations 

 have been made with iodine, and various fatty bodies, always with similar results. 



Transit of Titan. — M. Chacornac has presented to the French Academy a 

 drawing of the passage of Titan over the disk of Saturn. In addition to the 

 shadow M. Chacornac perceived the satellite itself contrasting with the brilliant 

 bands in the centre of the planet— near the margin the satellite became invisible. 

 This phenomenon is the inverse of that which occurs when Jupiter's satellites 

 make their transits, and indicates a difference in the atmosphere of the two 

 planets. The observations were made with the great Foucault telescope. 



The Great Spiral Nebula. — In our last number we mentioned the exa- 

 mination of this wonderful formation in Canes Venatici, by M. Chacornac, with the 

 Foucault reflector. The following are the remarks of this astronomer in presenting 

 his drawing to the French Academy : — " We must first notice the stellar appear- 

 ance of the°luminous centres of this double nebula, and observe that the central 

 nebulosity of the greatest of them, has under high magnification the appearance of 

 a whirlpool of little stars environing a principal star, which has not the planetary 

 character indicated by Lord Eosse. These stars, of which those nearest the 

 centre are seen through a nebulous veil, are not the only novelties, for as many as 



