SCIENCE- GOSSIP. 



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CHEMISTRY 



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CONDUCTED BY HAROLD M. READ, F.C.S. 



The Biological Detection op Arsenic— A 



novel method for the detection of arsenic is pub- 

 lished in a recent issue of the " Zeitschrift fur 

 Hygiene." It has been noticed that when certain 

 moulds are cultivated in the presence of arsenic, 

 arsenical compounds, easily recognised by their 

 characteristic garlic-like odour, are produced. 

 Making use of this fact, Abel and Buttenberg take 

 the suspected material, powder it, and add it to 

 moist breadcrumbs. The mixture is sterilised in 

 a flask and the contents inoculated with Penieilliiim 

 brevicaule or Aspergillus glaucus. The flask is 

 then capped and incubated in a hot-temperature 

 incubator for two days. The presence of one- 

 tenth of a milligram of arsenic can be detected by 

 the garlic-like odour which is readily noticed on 

 removing the cap. 



Artificial Cold.— The first of a course of 

 lectures on " Methods of Producing Artificial 

 Cold *' was given at University College on Novem- 

 ber 9th by Dr. Hampson, the well-known authority 

 on this subject. The struggle towards the absolute 

 zero has been productive of such vast innovations 

 from an economic point of view, and at the same 

 time replete with such epoch-marking discoveries 

 on the purely scientific side, that the chance 

 of making a more exact acquaintance with the 

 subject will, no doubt, be seized by those who have 

 the opportunity. At the lecture referred to the 

 main theoretical question involved in the expansion 

 of a gas under pressure was discussed. The 

 natural deductions that, while a gas expanding 

 without doing work became cooler, the lowering 

 of temperature of a gas doing " power-expansion," 

 such as in working a piston, was infinitely greater, 

 were well exemplified by an experiment in which 

 air under a pressure of 130 atmospheres was 

 allowed to escape into the surrounding air from 

 the bottle in which it had been stored. We hope 

 to again refer to the lectures from time to time. 



The Carbides of Neo- and Praseo-dymitjm. 

 — M. Henri Moissan, in continuing his research on 

 the metallic carbides, describes in a recent issue 

 of the " Comptes Rendus " the crystalline carbides 

 NeC 2 and PrC,. One of the interesting features of 

 the paper is the comparative result obtained on 

 treating the carbides of the alkaline earths, of 

 aluminium, and of the two metals under notice, 

 with water. While aluminium carbide gives rise 

 to the formation of methane, the carbides of the 

 alkaline earths give acetylene ; and M. Moissan 

 now finds the neo- and praseo-dymium give a 

 mixture of hydrocarbons in which, however, 

 methane and acetylene predominate. This fully 

 bears out the position of the two rare metals rela- 

 tively to aluminium and the alkaline earths, for 

 they had already been placed in the cerium group. 

 The carbides of this group have the general 

 formula RC 2 . and give with water similar decom- 

 position products. 



CORRESPONDENCE. 



We have pleasure in inviting any reader- who desire to raise 



o as mi scientific subjects, to address t h-ir letter 

 Editor, at 110 Strand, London, W.O. I! nr onlj restrict 

 be, in case the correspondence exceeds the bounds of court.-. ; 



natter of - 

 letters may be anonymous. In that case they must i' 1 

 panied by the lull name and the writer, 



publication, buo ai an earn'- litordWs 



Dot hold himself responsible for the opinions of the curre- 

 nts. — E'l. S.-6. 



A PACIFIC OCEAN MYSTERY. 



To the Editor of SCIENCE-GOSSIP. 



Sir.— Easter Island, the nearest Polynesian island 

 to South America, and in a direct line with Chili, 

 is a small island well known as being crowded with 

 prehistoric remains. Innumerable statues, Cyclo- 

 pean houses, and other relics of some vanished 

 race exist, resembling somewhat in character the 

 Central American and Peruvian monuments of 

 antiquity. Roggewein, a Dutch explorer, visited it 

 in 1721, and found there a semi-civilised race of 

 aborigines, apparently sun-worshippers, as were 

 the Incas of Peru. They worshipped also tin- 

 gigantic idols which stand on platforms along the 

 coast, and having artificially distended ears, also 

 like the inhabitants of Central America and Peru. 

 They were without weapons, and apparently gentle 

 and most peaceable. 



Since then a Polynesian invasion — the most 

 easterly expedition of that maritime race — over- 

 whelmed them, under a leader called Hotu-Matua. 

 so that when Cook reached the island, on his 

 second circumnavigation in 177-1, he found the 

 inhabitants to be ordinary Malay-Polynesians, 

 almost savages, knowing nothing of the antiquities 

 of the island or of their origin. Not any of the 

 islanders in Cook's time exceeded six feet tall. 

 This is remarkable, as Roggewein and his com- 

 panions most solemnly asserted that the aborigines 

 they found there were of gigantic height They 

 said : " Ali these savages are of more than gigantic 

 size : for the men being twice as tall and thick 

 as the largest of our people, they measured, one 

 with another, the height of twelve feet. . . . Ac- 

 cording to their height, so is their thickness, and 

 all are, one with another, very well proportioned, 

 so that each could have passed for a Hercules." 

 It is added that the females do not altogether 

 come up to this, " being commonly not above ten 

 or eleven feet." Cook and all subsequent voyagers 

 have supposed that this was mere romancing ; but 

 I have discovered a slight parallel to this in the 

 account of a recent voyage in Polynesia. 



In 1898 H.M. ship "Mohawk" was cruising 

 amongst the Santa Cruz, Swallow, Reef and other 

 islands, about four or five hundred miles east of 

 the Solomon Islands, when there was found an 

 apparently new and overlooked race occupying 

 Tocupia, one of the Reef and Swallow group. 

 They numbered some eight hundred souls, and 

 were gigantic in stature; one measured 6 feet 

 10 inches. The women were proportionate. The 

 men had long, straight hair, which they dyed 

 a flaxen colour, and which in thick folds 

 hung over their copper-coloured shoulders. The 

 women, on the contrary, had their hair cut 

 short. Strange to say. these natives had no 

 weapons of defence. They were not Kanakas, 

 ordinary Malay-Polynesians, or woolly-haired or 

 stunted in stature— in fact very different from 



