382 



THE POPULAR SCIENCE MONTHLY 



drawings arc made with water-colors, the 

 body of which is wiiite-lead. Those por- 

 tions of the surface which are not painted 

 are covered with varnish. The article is 

 then placed in dilute nitric acid, whereby 

 the paint is dissolved, and the surface of 

 the metal is etched to a certain depth. The 

 article is then washed with water, and im- 

 mediately placed in a silver or gold bath, 

 and a layer of the precious metal deposited 

 by electricity on the exposed portions. 

 When the latter operation is finished, the 

 varnish is removed, and the whole surface 

 ground or polished, so that the ornamented 

 portion is just even with the rest of the sur- 

 face. A specially fine effect is obtained by 

 producing a black bronze of sulphuret of 

 copper on portions of the surface between 

 the silver ornaments. A copper vase then 

 has three colors, black and white drawings 

 on a red-brown ground of suboxide of cop- 

 per. 



Ancestors of the Esqaimanx. Charles 

 E. DeRance, in one of his papers on " Arctic 

 Geology," points out some of the many 

 striking resemblances between the modern 

 Esquimaux and the paleolithic man of 

 Southern France. These two peoples, sepa- 

 rated so widely in time and space, were alike 

 in their artistic feelings and methods of in- 

 cising, on tusks, antlers, and bones, repre- 

 sentations of familiar objects ; alike also in 

 their habit of splitting bones for marrow, 

 and accumulating them around their dwell- 

 ings ; in their disregard for the sepulchre of 

 their dead ; in their preparation of skins for 

 clothing, and in the pattern of the needles 

 used in sewing them together; alike also 

 in their feeding on the musk-sheep and the 

 reindeer, and in countless other character- 

 istics. It is wellnigh impossible to resist 

 Prof. Dawkins's conclusion that the Es- 

 quimaux is the descendant of paleolithic 

 man, who retreated northward with the arc- 

 tic fauna with which he lived in Europe. 



Antidote to Atropia. Dr. G. Riickert 

 has made the interesting discovery that the 

 poisonous alkaloid muscarin (extracted by 

 alcohol from the mushroom Amanila mits- 

 caria) is a perfect antidote to atropia, and 

 vice versa. The pupil of the eye, enlarixed 

 by atropia, is contracted by muscaiin. So, 

 too, the depression of temperature induced 



by subcutaneous injection of muscarin is 

 counteracted by the other alkaloid similar- 

 ly injected. The heart of a frog, whose 

 action had ceased from thirty to sixty min- 

 utes under the influence of muscarin, had 

 its activity restored by the exhibition of 

 atropia. The relation of quinine to the spe- 

 cific poison of intermittent fevers is prob- 

 ably analogous to that between these two 

 alkaloids. 



NOTES. 



Correction. Prof. Henry Wurtz cor- 

 rects an error in the theory of A. McDougall, 

 of the Manchester Literary and Philosoph- 

 ical Society, on the possible mode of form- 

 ation of graphite, as given in our Notes for 

 last month. As he points out, the carbon 

 which collects in gas-retorts does not give 

 the reactions of graphite with a mixture of 

 chlorate of potassium and nitric acid ; it is 

 not converted into graphitic acid ; therefore 

 it is not graphite at all, and of course its 

 formation cannot explain the formation of 

 that mineral. It has even been shown by 

 Berthelot that gas-retort carbon contains 

 hydrogen, being in fact a highly-condensed 

 hydro-carbon, or mixture of hydro-carbons. 



The Aniline Manufacturing Company, of 

 Berlin, are now producing aniline colors by 

 Coupler's process, in which no arsenic acid 

 is employed. Being free from arsenic, these 

 dyes are not only fitted for coloring sweet- 

 meats, liqueurs, syrups, and pharmaceutical 

 preparations, but may be used in many 

 other industrial purposes where poisonous 

 colors would be more or less dangerous, as 

 in the staining of paper, paper-hangings, 

 toys, etc. 



A. FLAME burning in condensed air grad- 

 ually increases in brilliancy with the com- 

 pression, till at last it becomes as brilliant 

 as the flame of phosphorus in oxygen. But, 

 if the pressure be still further increased, 

 the process of combustion is retarded, and 

 the flame becomes smoky. From this it 

 would appear that the temperature of com- 

 bustion increases with the pressure up to 

 the point of dissociation of the hydro-car- 

 bon gases of the candle. Hence the con- 

 clusion that it is an error to estimate the 

 temperature of the sun at several millions 

 of degrees. Sainte-Claire Deville holds that 

 2,000 C. is the highest possible tempera- 

 ture. 



ScHWEiNFURTH, the distinguished Afri- 

 can traveler, has been appointed by the 

 Kliedive Director-General of all the large 

 collections, museums, and other scientific 

 institutions, of Cairo. 



