July 27, 1882] 



NA TURE 



309 



formed in a tube to which the heat of a Bunsen burner was 

 admitted (through a rock-salt plate) ; and the resultant variations 

 of pressure were recorded by means of a Knoll pant 

 '1'he curve obtained (with percentages as abscissae and indicated 

 recorded as ordinate-) shows, as one might expect, a 

 decrease 01 rise of pressure through a' sorption of heat, with 

 of CO;,, but the two are not proportional. With regular 

 decrease of CO.. from 100 per cent., the fall is slight, in the 

 curve, to about 5 per cent., and thereafter rapid to zero with 

 pure air. (Mixtures of CO s and H give a different curve, with 

 a much lower position throughout.) By chemical methods the 

 CO„ has been shown to vary between C02 and o - 05 per cent. 

 Hence it was desirable to develop the corresponding part of the 

 1 described with special care. This was done, and 

 eric air, freed from moisture, bat not from CO a , was 

 admitted to the apparatus. The tabulated results of fifty analyses 

 made thus, in four days, at Giessen, appear to prove the appli- 

 cability of the method. (The pio; ortion of CO._, varied between 

 C020 and C034.) Its advantages are : only small quantities of 

 air (one or two litres) being required, and the operati 

 quite simple, and taking little time (say half an hour). It is 

 suggested that the aqueous vapour in air may be similarly 

 measured. 



A third instalment of researches on transpiration of vapours, 

 by Herr Steudel, at the instance of Prof. I.othar Meyer, is 

 described in Wied. Ann. No. 7 ; it relates to alcohols and their 

 halogen derivatives, and to some substitution-products of ethane 

 and methane. In a concluding paper Prof. Meyer reviews the 

 inquiry. The supposition i- confirmed, that ho 1 ologous series, 

 even with very different molecular weight, have for the 

 nearly the same constants of friction. (All compounds contain- 

 ing one carbon atom show strong divergence.) The influence of 

 the nature of the contained atoms, on friction, is remarkable. 

 1 hus, with about equal molecular weight, iodine produces a 

 much greater friction than bromine, and the latter a greater than 

 Far-reaching conclusions as to the form of molecules, 

 Prof. Meyer is not prepared to draw-, but the cross section of the 

 molecule of a tertiary butylic Compound is inferred to be less 

 than that of the corresponding secondary, and the latter less than 

 that of the primary. I his agrees with received views as to the 

 linking of these compounds. The molecular volumes reckoned 

 from the friction of vapours, stand to each other in nearly the 

 same ratios as the molecular volumes in the liquid state at 

 boiling point. 



FROM observations made several years ago, Prof, von Reusch 

 ol Tubingen was led to think the hydrophane of Czernowitza 

 a sub.-tance peculiarly well fitted for diffusion experiments with 

 gases. Its properties in this relation have now been carefully 

 studied by Herr Hufner {Wied. Ann. No. 6) ; and in 

 is show 11 that the resistance t 1 passage of a number of gases is 

 related both to the coefficient n and the specific 



gravities ; all three increasing in the same sense (but not in 

 simple proportion). 



An interesting analogy to thermoelectric phenomena, &c, is 

 given by M. Bouty in the Journal de Physique (June). Suppose 



ling, impermeable to hear, containing in its 

 sand saturated with water, and in its upper air saturated with 

 water-vapour. If heat be appliei (a) of the sand, a 



circulation is set up, the water being vaporised at A, condensed 

 at the opposite end u, and filtering through the sand to replace 

 the water evaporated at A. Again, suppose (instead of heat) 

 a rotary pump acting about .the middle of the air space ; a circu- 

 lation is produced, and the water evaporating at A causes a fall 

 of tem;>erature, while the condensation at u cause- a rise ; an 

 image is thus presented of Peltier's phenomenon. The junction 

 A, which is cooled, is precisely the one which must be heated to 

 produce the existing circulation, and the quantity of heat absorbed 

 at A is proportional to the weight of water evaporated per second, 

 that is, to the intensity of the current. 



SlGNOR Martini (.V. Cim. [3] 9, 1SS1) obtains diffusion 

 figures thus: A glass vessel is filled with two liquids little differ- 

 ing in density, e.g. water and an aqueous solution of salt or sugar. 

 They are left at rest for an hour. A capillary tube entering the 

 bottom of the vessel is connected by caoutchouc tubing with a 

 movable vessel of coloured alcohol. When the latter enters by 

 the capillary, it rises as a thin spiral thread, but on reaching the 

 lighter liquid it spreads into fine tree-shaped figures. Figures of 

 umbrella shape are produced, if the heavier liquid be used in 

 place of the alcohol. 



Prof. T. C. Memjexhall, of Columbus, Ohio, communi- 

 cates to the American Journal 0/ Science a pii| er on the Influ- 

 ence of Tune on the Change of Resistance ol the Carbon Disk 

 - Ta.-i meter. This resistance was found, when 

 pressure was removed suddenly, to return to its maximum value ; 

 but when pressure was applied, time was necessary to enable the 

 resistance to reach its minimum. On applying pressure, the 

 resistance fell a little more than 3 per cent, in one minute, about 

 5 per cent, iu three minutes, and about 10 per cent, in one and 

 a half hours. 



Contrary to the opinion now generally received concerning 

 the alleged change of resistance of carbon under pressure, M r. 

 Mendenhall, in the communication alluded to in the preceding 

 note, asserts that the effect is not due to better surface Contact. 

 His own experiments were made with one of Edison's com- 

 pressed lampblack buttons resting iir its place in the tasimeter, 

 and covered by an "upper contact piece." This is all the 

 information given upon this vital point of how the contacts were 

 made, and in the absence of any evidence of care or precautions 

 to ascertain whether the contact was perfect or not, the opinion 

 pronounced must be regarded as worth very little. 



GEOGRAPHICAL NOTES 



The Journal of the Straits Branch of the Bengal Asiatic 

 Society for December, 18S1, contains a short comparative voca- 

 bulary of the Fijian and Maori (New Zealand) languages, with 

 notes by Mr. Thurston and Sir F. A. Wild. The Maori is a 

 recognised member of the Eastern Polynesian linguistic family, 

 and from these specimen.- the Fijian might be supposed to 

 belong to the same connection. But the natives, especially of 

 the eastern i.-lands of the Fiji Archipelago, have long been ex- 

 ilynesian influences, through their relations with the 

 Tonga i-landers. These influences are apparent both in their 

 physical type and in the numerous dialects current on the coast. 

 But ihe skulls of the Kai Colos occupying the interior of Viti 

 Levu have been show n by Prof. Flower to be of a distinctly 

 Papuan character. In fact, they are the most dolichocephalic 

 on the globe. The outward appearance of the Kai Colos and 

 other tribes removed from contact with the Tonga people also 

 closely resembles that of the pure Melanesians of the New 

 Hebrides and Solomon groups. Specimens of their speech have 

 not yet been collected ; but it may be taken for granted that it 

 will be found to be of a distinctly Melanesian type, betraying 

 little or no affinity to the Polynesian. Such vocabularies as 

 these, while possessing a certain value, are apt to be very mis- 

 leading, anel have in fact contributed to the current belief that 

 the Polynesian and Melanesian tongues are fundamentally one. 

 In reality they possess nothing in common beyond the verbal 

 resemblances due to the wide-spread Polynesian influences in 

 the Melanesian domain. In their morphology and inner struc- 

 ture, the two systems are radically distinct. 



HlRT, of Breslau, has published a second part of the " Geo- 

 graphische Bildertafeln," by Dr. Oppel and Heir Arnold 

 Ludwig, the first part of which we noticed recently. This part 

 is devoted to typical landscapes, and the selection seems to us to 

 have been made with great discrimination. For Great Britain, 

 for example, we have Loch Ness in Scotland, a Sc 'tch Moor, 

 the Giants' Cau,eway, the Dover Coast, a Welsh Valley, and 

 an extensive landscape on the Upper Thames. All the other 

 leading countries of Europe are treated after a similar fashion, 

 while representative scenes are given from the great divisions of 

 the other continents. The interest and utility of such a collec- 

 tion are obvious. The same publisher i-sues also a coloured 

 panorama, showing the chief forms of the land and water on 

 the surface of the globe, much superior to the publications of 

 the same class with which we are familiar in this country. 



Lieut. Giraud has sailed from Marseilles for Zanzibar, as 

 leader of a French expedition which proposes to take up African 

 exploration where Livingstone laid it down with his life on the 

 south shore of Lake Bangweolo. Lieut. Giraud proposes to go 

 either direct west to Lake Tanganyika, or, more probably, by the 

 north shore of Lake Nyassa, to the Chambeze River. This he 

 will follow to its outlet in Lake Bangweolo, which he proposes 

 to circumnavigate. He will then attempt, in canoes, to sail 

 down the Luababa- Congo, to its mouth in the Atlantic Ocean. 

 This is an ambitious programme ; and every one interested in 

 African exploration will wish the expedition complete success. 



