522 



NA TURE 



yApril 12, 1877 



eccentric position within the glass vessel such an influence of the 

 walls should be readily recognised. He describes a number of 

 experiments made in this way, and which he regards as support- 

 ing the second view. 



In an article contributed to Fo^gendorffs Annalen, M. Zollner 

 is led to take the following positions in reference to the radio- 

 meter. The explanation of radiometric motions based on the 

 principles of the mechanical theory of gases, makes suppositions 

 about the relation of the mean lengths of path of the gas mole- 

 cules to the dimensions of the vessel which are not realised in 

 fact. This explanation further leaves out of consideration, with- 

 out sufficient ground, the simultaneous existence of mercury 

 vapours whose molecules have a more than seven times greater 

 mass and a much smaller mean length of path than the mole- 

 cules of the gas acting according to the mechanical theory of 

 gases. Hence we are not warranted in regarding the radiometric 

 motions discovered by Crookes as an empirical confirmation of 

 the mechanical theory of gases. 



Berlin dealers in delicacies have recently received from the 

 south, and especially from Upper Italy, immense quantities of 

 edible birds which have been captured there in their flight north- 

 wards. Unfortunately there were not only snipe, fieldfare, and 

 larks, or so-called "delicacies" among the birds sent, but also 

 singing birds, that are never eaten in Germany, such as gold- 

 finch, thrush, and nightingales. The animals were caught on 

 their migratory flight by means of nets, or surprised during the 

 night and indiscriminately killed. A new indication of the im- 

 portance of an international law for bird protection ! 



An exhibition of objects relative to pre-historic archaeology 

 will be opened shortly in Moscow, and promises to be very 

 interesting. 



An elaborate volume just published by the Federal Statistical 

 Bureau of Switzerland, gives the number of scientific societies in 

 the country in 1875 as 46, with 54,955 members. The societies 

 for educational purposes numbered 816, with 54,424 members. 



The municipal authorities of Berne have set aside the sum of 

 24,000/. for the foundation of a Museum of Natural History in 

 that city. 



Associations and Committees are being formed in most of 

 the large towns of the Netherlands with the object of " fitting 

 out a suitable vessel for Nova Zembla and other stations of in- 

 terest in the Arctic regions." The avowed aim of the expedition 

 is not the discovery of the Pole, but the erection of some unpre- 

 tentious granite monuments to the memory of the glorious dis- 

 coveries of the earlier Dutch navigators. About the end of the 

 seventeenth century, " in the name and on behalf of the honour- 

 able Council of the renowned City of Amsterdam," Willem 

 Barends set out on his third voyage, which ended in the ex- 

 plorer's wintering on Nova Zembla, v/hence he never returned. 

 It is, above all, the memory of Barends which the Dutch 

 are about to honour. The costs of the expedition are to be 

 defrayed by voluntary subscriptions, and the vessel will, in all 

 probability, be commanded by a Dutch lieutenant who has taken 

 part in three Arctic expeditions under the British flag. 



The Committee of the German Afiican Society has issued an 

 appeal for help towards the establishment of a series of perma. 

 nent stations in Africa, so as gradually to narrow the area of the 

 unknown country, to serve as centres of culture, and to be depots 

 for information and for trade with the natives. The effort would 

 be in sympathy with that of the International Congress at 

 Brussels, and the appeal is made specially to Germany to main- 

 tain the exceptionally high place she has taken in the scientific 

 discovery of Central Africa, 



Geographical students will be glad to learn that an index to 

 Petermann's Mittheilungen aus Justus Perthes's geographischer 



Anstalt iiber Wichiis;e neue Erforschungen auf dem Gesammt- 

 gebiete der Geograpkie has been published for the period between 

 and including the years 1865 to 1874. The value of this is 

 greatly increased by the publication therewith of index maps, 

 which show at a single glance those parts of the world of which 

 maps have been published in the Mittheilungen during the period 

 in question, with references to the places where they have 

 appeared. 



Gen. Uchatius ba?es his invention of the steel bronze, or 

 more correctly, hard bronze, cannons, now introduced into the 

 Austrian service, on the observation, that all metals (with excep- 

 tion of lead and zinc) have their elasticity increased, when they 

 have undergone a continuous weighting above their first limit of 

 elasticity. In the first February number of Dingier' s polytech- 

 nisches Journal, M. Uchatius gives, in reply to the objections 

 of some technologists, the results of further experiments, which 

 appear to show that even homogeneous bronze is capable of a 

 great increase of its elasticity through simple stretching, without 

 condensation. It is only a stretching of the metals above their 

 limit of elasticity, whereby the' molecules, brought to a state of 

 flow, glide over each other, and assume a wholly new position 

 more favourable to resistance,' that causes the increase of elasti- 

 city. A simple condensation produces merely an increase of 

 the absolute solidity and diminution of the tenacity, but no real 

 increase of elasticity. The limit of elasticity may be raised 

 nearly to the breaking consistence, so that in many cases it is six 

 and seven times the original. Mere stretching for a short time 

 is of little use ; the tension must act a considerable time. It is 

 also well to apply a gradually increasing weight. 



A singular fact with reference to the production of heat is 

 described by M. Olivier [Comptes Rendus). A square bar of 

 steel 15 mm. in width and 70 to 80 ctm. long is seized with the 

 two hands, placed, one at one end, the other in the middle of 

 the bar. The other end is pressed agamst an emery grind-stone 

 rotating rapidly. In a few minutes the rubbed end is consider- 

 ably heated. The band at the middle has no sensation of heat, 

 but that at the extremity is strongly heated, so that it has to be 

 taken from the bar. Thus, in certain cases, heat appears not to 

 be propagated in metals from one part to that next it. 



In the year 1824 M. Wohler made the observation that pal- 

 ladium, whether in the form of sponge or of polished sheet, has 

 the property of becoming sooty in a spirit flame, and gradually 

 coated with a thick layer of carbon. A piece of spongy palladium 

 will thus be enlarged to several times its original volume. The 

 same phenomenon occurs if the metal is made to glow in a coal- 

 gas flame. If the deposited carbon be burnt, there remains 

 always a fine skeleton of palladium, which is then found to be 

 penetrated with the carbon and quite brittle. By more recen 

 experiments M. Wohler convinced himself that the pheno- 

 menon is not due to a special affinity of palladium for carbon. He 

 is rather of opinion that the strong absorption power of this metal 

 for hydrogen is the reason why ethylene gas and the gases of 

 the spirit flame, which themselves are not absorbed by palla- 

 dium, are decomposed under the influence of this metal, as the 

 experiments show, with separation of carbon. 



Led by speculative considerations regarding the formation ot 

 the earth, M. Sacher, of Salzburg, made experiments a short 

 time ago on the solidification of balls of spermaceti floating freely 

 in a liquid, and he has more recently experimented on the pro- 

 pagation of heat in unequally dense liquids. In a beaker glass, 

 16 ctm. high, he put five layers of alcohol varying in density 

 from 0*98 to 0*82, and each 3 ctm. thickness. Three thermo- 

 meters were placed with their bulbs in the first, third, and fifth 

 layers respectively, and the vessel was slowly heated from below. 

 In another similar vessel containing liquid all of the same density, 

 the three thermometers showed nearly the same temperature ; 



