July 12, 1900] 



NATURE 



253 



•observatory. They have curved flying surfaces rnodelled after 

 the wings of a bird. The three kites nearest the top of the line 

 had an area of between 60 and 70 square feet each, and the two 

 others about 25 feet each. The total weight lifted in'o the air, 

 including wire, instruments and kites, was about 130 lbs. 



Mr. E. G. Green, Government entomologist at the Botanic 

 •Gardens at Peradeniya, Ceylon, has recently been able to con- 

 firm by personal observation the web-spinning habits of the red 

 ant (CEiophiia sinaragdina). He has seen ants actually holding 

 larvce in their mouths and utilising them as spinning machines. 

 To find what would be done, some leaves which had been newly 

 fastened together by the ants were purposely separated by Mr. 

 •Green. The edges of the leaves were quickly drawn together 

 •by the ants, and, about an hour later, small white grubs were 

 seen being passed backwards and forwards across the gaps made 

 in the walls of the shaker. Each grub (there were apparently 

 only two of them) was held in the jaws of one of the worker 

 ants, and its movements directed as required. A continuous 

 thread of silk proceeded from the mouth of the larva, and 

 was used to repair the damage. There were no larvre amongst 

 the occupants of the disturbed iaclosures, and the grubs used for 

 spinning were apparently obtained from a nest a short distance 

 away, which probably accounts for the considerable time that 

 •elapsed before the rent was repaired. 



The temperature of the free air is the title of a paper com- 

 municated by Dr. Hergesell to Part V, of PeUrmantCs 

 Geographische Mitteihingen. We have frequently referred to 

 tl\p great importance of this subject and to the valuable work 

 performed by Dr. Hergesell in organising ascents of manned 

 and free (or unmanned) balloons, and in discussing the results 

 of the observations obtained. In the present paper he collects 

 and discusses the most recent materials, and deals especially 

 with the daily range and the vertical decrease of temperature in 

 the upper strata of the atmosphere. The observations show 

 that even at a height of a few hundred metres, there is a very 

 small diurnal range ; at night-time it amounts, in some ascents, 

 to only a few tenths of a degree, and in the day-time, at about 

 800 metres, to some 3° or 4° Centigrade, when solar radiation is 

 unobstructed. On cloudy days, and in the mean values, the 

 daily amplitude is much less. With respect to the vertical 

 decrease of temperature, the results of thirty sets of observations 

 show that in all levels up to 10,000 metres an extremely varying 

 temperature obtains, according to the season of the year and 

 the conditions of weather. The decrease at that height reached 

 or exceeded 40° C. in all cases, but no fixed rule could be laid 

 down as to the regular decrease with altitude. 



A RECENT number of the Scientific American contains a very 

 interesting account of the use of a diver for the collection of 

 zoological specimens that has been made in the Bay of Avalon, 

 California. A large double-ended surf boat, in which the pump 

 was placed, was towed to the scene of operptions and anchored 

 securely, bow and stern. Besides this, a number of observation 

 boats, with glass bottoms, were used, and through these every 

 movement of the diver could be observed. As soon as the 

 diver was ready to descend, a scoop-net and a spike were handed 

 to him. Stepping down, round by round, he finally pushed off 

 and slowly sank to the bottom in about twenty-five feet of 

 water. Through the glass bottom of the observation boats every 

 movement could be plainly seen, as the diver walked through 

 the weed, parting it on each side with ease, and collecting such 

 specimens as seemed desirable. In one walk he brought up 

 angel fishes, star fishes, holothurians, echini, a number of large 

 univalve shells, a living shark, and numbers of small shells. 

 The result of two days' work demonstrated the value of this 

 method of collecting specimens, as in using a dredge many of 

 the most delicate forms were injured. Where a diver is used it 

 NO. 1602, VQJ^, 62] 



is not necessary to take them from the water, the specimens 

 being transferred in the water from the wire collecting-basket 

 to a glass jar. The experiments are stated to have proved 

 beyond question the value of the diver in work of this kind, as 

 the ground covered was a veritable forest of macrosystis, in 

 which groups of rocks were scattered, making work with a 

 dredge impos-sible. 



The Russian steamer Rurik has arrived at Tromso, from 

 Spitsbergen, bringing news from the Russian expedition, which 

 had wintered on the island for the measurement of an arc of the 

 meridian. No news could be sent until now, because the carrier- 

 pigeons which the expedition set free on Spitsbergen refused to 

 fly southwards and obstinately returned to the wintering place. 

 The Rurik probably brings in a full report from the chief of the 

 expedition. Prof. Th. Tchernysheflf, but from a telegram of the 

 learned geologist, which was sent to the Academy of Sciences 

 from Tromso, we already learn that all members of the ex- 

 pedition were well. During the winter astronomical and 

 physical observations were made according to the programme. 

 Photographs were taken of aurorre and their spectra, and in the 

 spring observations were made on Mount Keilhaus, at the 

 signal-pillar of the meridian arc. South Spitsbergen was crossed 

 several times. Akhmatoflf made pendulum measurements on 

 Mount Keilhaus. The state of ice was still unfavourable in 

 Storfjord, and Prof. Tchernysheff's intention was to make more 

 excursions and, leaving the " ice-breaker" at Storfjord, to try 

 to reach the Swedish party at Seven Islands. 



The Transbaikalian Railway will be opened for traffic this 

 month. It begins at Irkutsk, wherefrom a line, forty miles 

 long» goes to Lake Baikal. There the train is placed on an 

 ice-breaker-ferry and is transported to the Mysovskaya Station 

 on the eastern shore of the lake, whence it runs 665 miles pas 

 Verkhneudinsk, Chita, and Nerchinsk (the town— not the 

 mines) to Sryetensk. Steamers ply regularly during the summer 

 from this little town down the Shilka and the Amur to its 

 mouth. At the station Kaidalova, near Chitri, begins the rail- 

 way across Southern Transbaikalia, Mongolia, the Great 

 Khingan Mountains and Manchuria, vid Tsitsikar (on the 

 Nonni) and Mukden, to Port Arthur. Work is busily carried 

 on along this last line, building going on on several .sections at 

 once : in Transbaikalia, at Tsitsikar, and at the southern end 

 of the line. 



Messrs. Cadett and Neall have sent us a sample of their 

 X-ray paper. It is claimed for this material that a great reduc- 

 tion in exposure is effected as compared with the most rapid 

 dry plates, about one-eighth of the usual exposure being all that 

 is required. The paper has also the advantage over glass plates 

 of freedom from risk of breakage, flexibility and consequent 

 adaptability to the object to be photographed, and portability. 

 The reason for paper of this description requiring so much less 

 length of exposure than ordinary dry plates, is because less density 

 is required for a reflecting surface to show structure than is re- 

 quired for a plate from which prints are required ; consequently, 

 with the X-ray paper, and using a lo-inch coil with a good tube, 

 a good print of a hand can be obtained with about two seconds 

 exposure ; or, using an electrolytic break with the coil, with less 

 than one second exposure. 



An ingenious machine for solving any algebraic equation of 

 the form /x» -1- /jt'U + /2^"' + &c. = A, by an application of 

 the principle of Archimedes, is described by M. Georges Meslin 

 in the Journal de Physique for June. It consists of a beam 

 balanced on a knife-blade from any point of which may be 

 suspended a solid of revolution, and a series of such solids is 

 provided, constructed in such a manner that in the solid of 

 order n the volume cut off by a horizontal plane is proportional 

 to the »th power of the distance of the .horizontal plane from 



