NOTES. 



43i 



The experiments instituted by M. Pictct > 

 to determine the density of liquid oxygen, 

 hydrogen, and nitrogen, have been followed 

 up by Messrs. Gailletet and Hautefeuille, 

 who hare facilitated the processes by previ- 

 ously mixing the gases with carbonic acid 

 and protoxide of nitrogen, whereby the 

 liquefaction is made to take place more 

 readily. The density of the liquids of the 

 latter gases being known, it is easy to com- 

 pute that of the substances under examina- 

 tion. The results of tests made at a very 

 low temperature are favorable to the theory 

 of the relations that have been suggested 

 between hydrogen and magnesium, oxygen 

 and sulphur, nitrogen and phosphorus ; but, 

 as the freezing-point of water is approached, 

 discrepancies are manifested which grow 

 more and more accentuated. 



Dr. Luton, of Rheims, reports that he 

 has discovered that the tincture of ergot of 

 rye associated with phosphate of soda pro- 

 duces on those to whom it is administered an 

 hilarious excitement, similar to that which 

 is brought on by laughing-gas. 



M. Lenz, in a communication made re- 

 cently to the French Geographical Society, 

 on his journey to Timbuctoo, says that in 

 the Inguidi, a region of sand - dunes, he ob- 

 served the equally rare and interesting phe- 

 nomenon of resounding or musical sand. 

 "All at once," he said, " there was heard in 

 the desert, issuing from a dune of sand, a 

 prolonged, muffled sound, quite like the 

 sound of a trumpet. It continued for some 

 seconds, then ceased, to be resumed in an- 

 other direction. The phenomenon made the 

 traveler anxious. I suppose it was occa- 

 sioned by the friction upon each other of 

 the burning grains of quartz, which are 

 simply placed one by the other, and are con- 

 tinually in motion." 



M. C. Widejian has shown that the elec- 

 trical qualities which are already plainly per- 

 ceptible in most kinds of paper can be 

 greatly increased by subjecting it to a pre- 

 vious treatment. Common unsized paper, 

 Swedish filtering paper, or silk paper, when 

 dipped in a mixture of equal volumes of 

 nitric and sulphuric acids, washed and dried, 

 becomes imperfectly transformed into py- 

 roxile, and extremely electric. When put on 

 a wooden table or an oil-cloth, and rubbed 

 with the hand, it will immediately at- 

 tract light bodies ; if taken up from the oil- 

 cloth in the dark, the whole surface shines 

 like phosphorus; when the finger is brought 

 toward it, it gives off a spark. A Leydcn- 

 jar may be charged with it. It gives off, 

 when rubbed, the characteristic odor of 

 ozone. It preserves its properties for a 

 long time, and may have them restored by 

 heating it. Thus, for a few cents, we may 

 possess a machine competent to aid in the 

 illustration of all electrical phenomena. 



Professor Lebour, of Newcastle, in a 

 paper on the geological distribution of en- 

 demic goitre in England, has shown that 

 the conditions of the prevalence of this dis- 

 ease are substantially the same as they have 

 been shown by the researches of Dr. de St. 

 Lager, of Lyons, to be in France. In both 

 countries the formations in which the most 

 goitre is supported are both calcareous 

 and metalliferous. .Metalliferous impurities 

 alone do not promote the disease, for the 

 Devonian and granitic formations are free 

 from it. The absence of limestone alone 

 does not prevent it, for it exists on the 

 lignitiferous beds of France, and the fer- 

 ruginous sands of the weald. Dr. de St. 

 Lager believes that endemic goitre coincides 

 with metalliferous deposits, of which iron 

 pyrites is most active. 



Professor Cope, describing the Canidce 

 of the Loup Fork, or highest Miocene forma- 

 tion of the West, represents that the num- 

 ber of species is not so great as in the pre- 

 ceding periods of the Miocene, while those 

 that are known more nearly approach the 

 existing dogs in character, aad are of a 

 larger average size. 



Dr. J. Youxg and Professor G. Forbes 

 have made some new researches to measure 

 the velocity of light, by the method that was 

 employed by M. Fizeau and M. Cornu. The 

 electric light was used, with two reflectors 

 a quarter of a mile apart, and a revolving 

 toothed wheel was employed to alter the 

 intensity of the reflected light. Through 

 this two stars of light were seen, one in- 

 creasing, the other diminishing in intensity 

 as the speed of the wheel was increased. 

 The speed required to produce equality of 

 the light was determined by means of a 

 chronograph. The final result of the mean 

 of the several observations for the velocity 

 of the light from an electric lamp in vacuo 

 was 187*273 miles a second. The observa- 

 tions on the color of the stars indicated that 

 the blue rays travel faster than red rays, 

 with a difference equivalent to about 1*8 

 per cent, of the whole velocity. 



Professor Raoul Pictet, of Geneva, 

 announces the discovery of a method of 

 construction for greatly increasing the speed 

 of vessels by making such an arrangement 

 of the keel as will diminish the resistance 

 of the water to the lowest point. Where it 

 is applied, the prow, instead of sinking 

 deeper as the speed increases, will be raised, 

 and only the sides of the hull and the neigh- 

 borhood of the wheel will be exposed to the 

 friction, so that the vessel will glide over 

 the water instead of having to push its way 

 through it. Professor Pictet expects to at- 

 tain a speed of from thirty to thirty-six miles 

 an hour. A vessel embodying his plans is 

 building for Lake Leman. 



