April 7, 1882.J 



♦ KNOWLEDGE ♦ 



495 



WEATHER DIAGRAM. 



FOR WEEK ENDING SATURDAY, APRIL 1. 



Statiaii 



DyrfWeA 



3 ii 



CD.g 





flMTWiT'F S 



eiMlTiW.TiFiS 



Ikilllllll 



bbp cboo 

 C 



. I 



LIVERPOOL 



boo o cmo 



000 



piMlTlWiTlFls 



LI 



>fTi-/! 



o b c dblab 



r J 



5 



00000 



VALENCIA 



BiMjT W'TiFlS 



JIKU 



coo ob r c 



1 1 1 1 



Weather. — Veau/ort .SVaJe is, b. bine sky; c. detached clouds; 

 d. drizzling rain ; f. fog; g. dark, gloomy ; h. hail; I. lightning; 

 m. misty (hazy); o. overcast; p. passing showers ; q. squally; r. 

 rain ; s. snow ; t. thunder ; u. ugly, threatening ; T. visibility, un- 

 asual transparency ; w. dew. 



AMALGAMS. 



OPINION is still divided with regard to the nature of amalgams, 

 some considering them to be isomorphous mechanical mix- 

 tures, others true chemical compounds. The former ^new derives 

 support from those cases in which amalgamation is associated with 

 an absorption of heat, as in the solution of a salt or in dilution of 

 a solution ; the latter is supported by the fact that many amalgams 

 are formed with a strong development of heat. A contribution to 

 the subject has been lately made by Herren Merz and Weith, in the 

 Berlin Chemical Society. These chemists have investigated whether, 

 with regular heating, amalgams part with their mercury con- 

 tinuously or in distinct gradations. 



The experiments consisted in placing the amalgam in a porcelain 

 dish within a glass tube, contracted below, and inclosed in a second 

 tube, having a bulb at its lower end. This bulb of the outer tube 

 contained the snbstance of the vapour-bath (sulphur, mercury, or 

 diphenylamine). To guard the amalgam from air, a lively current 



of an indifferent gas was passed through the interior tube while the 

 experiment lasted. The amalgams used, which were always directly 

 produced by kno«Ti methods, contained on an average 60 to 80 per 

 cent, of mercury. This heating was continued, wherever possible, 

 until after several hours no decrease of weight (or hardly any) was 

 perceptible. There were examined gold, silver, copper, lead, tin, bis- 

 muth, zinc, cadmium, sodium, and ])otassium amalgams. The results 

 tor the first eight are very briefly communicated, those for the last 

 two, whose ea.sy oxidability required special precautions, more 

 fully. In the case of those alkali amalgams, the authors also 

 sought to determine the melting points, but, for certain reasons, 

 very accurate results were not reached. In general the melting 

 points of the amalgams rise at first very quickly with the propor- 

 tion of alkali metal, then gradual!}' fall. It was thus obsen-ed th".t, 

 when mercury is heated under paraffin to 250°, and then some 

 sodium is added in ])ortions, the whole mass solidifies with four to 

 five per cent, of sodium ; but with further addition of some per- 

 centages the mass fuses completely. 



The results of their investigation are summed up by the authors 

 as follows : — A survey of the results described shows, for a series 

 of amalgams, that even with moderate heating they do not furnish 

 determinate compounds. 



The amalgams of gold, silver, copper, bismuth, lead, tin, zinc, 

 and cadmium lose their mercury entirely, or nearly so even at or 

 under the boiling temperature of mercury. Where no mercury re- 

 mained, the cause is to be sought rather in a mechanical exclusion 

 than in a chemical action. But, on the other hand, the easy de- 

 composability of these amalgams evidently offers no proof that 

 there are no chemical compounds in them. 



For the rest, if we consider the great variability of amalgams,, 

 together with the fact that, in squeezing the so-called mercury 

 solutions of metals, these latter do not remain behind, but certain 

 mercury compounds, the view acquires the greatest probabilitv', 

 that at least very many amalgams may be, indeed, molecular com- 

 binations, but in fixed relations. 



ilost pronounced does chemism appear to be in the amalgams of 

 potassium and sodium. They lose their mercury extremely slowly, 

 even at the boiling point of sulphur, as also in a gas current, and 

 so in cii'cumstances highly favourable to removal of mere mixed 

 substances. The remarkable relations, too, as regards the meltiag 

 point, seem to speak for the presence of true chemical compounds. 

 Probably these amalgams, at a comparatively low, as well as at a 

 high temperature, consist of different compounds, none of which, 

 however, have a durable existence, and therefore recurrent, fixsd 

 relations of composition are not to be met with. Alkali-metal 

 amalgams of fixed composition wonld probably be obtained on jiro- 

 duction of larger quantities of amalgam ; perhaps also by heating 

 considerably above the boiling temperature of mercury. — Scientijie 

 Aynerican. 



Eea.so.n'int. Power in an Indian Crow. — Some years ago I sat 

 with my partner in the verandah of our ofilce at tiffin. Our regular 

 guest, a broken-legged crow, sat on the window sill. In the bread 

 basket was a piece of crust dried by the land wind as hard as a 

 brick bat. I threw it to the crow who picked at it many times, but 

 found it much too hard for his beak. He then evidently sat him- 

 self to find a remedy for so sad a state of things. He looked at it 

 with his head on one side, then he took another view of it from the 

 other side, and seemed faii'ly puzzled. All at once a bright thought 

 struck him, he seized the crust, flew with it to tlxe washhand basin 

 in the corner, shook the morsel well for a minute in the water, flew 

 back to his old place on the sill and gobled up the now soft crust 

 triumphantly. If that did not betoken reason I do not know what 

 could. — Kah Kah. 



St'ssE.K Akch.eological Society. — An interesting addition has 

 just been made to the already large collection of antiquities in the 

 possession of the society, deposited in Lewes Castle. It consists of 

 a cinerary urn, probably of the British- Romano period, about nine 

 inches in height. The vessel is of sun-dried clay, and about seven 

 inches in diameter at its widest part, the mouth being about five 

 inches. It was discovered by some labourers engaged in flint 

 digging on Mr. Homcwood's farm, at Jevington, a few days ago. 

 They were working at the foot of Jevington-hill, and came ujxm 

 several urns embedded in a quantity of loose flints, lying about two 

 feet below the surface of the down land. There were no tumuli or 

 other outward indications that the spot had been used as a burying- 

 place. Unfortunately, the greater part of these relics were destroyed 

 by the picks of the labourers before the nature of the discovery 

 became apparent. One, however, reniained intact, and this fact 

 was communicated to the hon. sees, of the society, who at once 

 organised an expedition to the spot. The visit was made on 

 Wednesday, and the " find" carried off in triumph. Those present 

 were the Kev. W. Powell, the Rev. P. de Putron, Mr. R. Crosskey 

 Mr. J. C. Lucas, and Mr. Griftith. 



