Jan, 31, 1878] 



NATURE 



269 



tube T T ; it reduces the space a b occupied by the gas, 

 and is soon surmounted by droplets of the compressed 

 gas, which unite into a little mass of liquid, b. 



The following are the parts of the apparatus :— 

 B, a block of malleable iron with strongly-resisting 

 walls ; e', e, screw nuts which may be unscrewed to 

 arrange the apparatus before using it ; P P, very solid 

 tripod which receives the apparatus ; s, support of the 

 bell G and the envelope M ; N supplementary screw 

 intended to close the hole in the joint R when the mer- 

 cury is poured into the apparatus. 



OUR ASTRONOMICAL COLUMN 



The Royal Observatory, Cape of Good Hope. — 

 Since the appointment of Mr. Stone to the directorship 

 of this establishment, in 1870, not only have all arrears of 

 observations with the transit-circle, first brought into use 

 in 1855, been reduced and published, but Mr. Stone has 

 lately issued the results of observations taken in 1875, 

 and has thereby overtaken the position of publications of 

 the Royal Observatory, Greenwich, and the Radcliffe 

 Observatory, Oxford, which have been conspicuous 

 amongst astronomical establishments for the expedition 

 with which the great mass of work involved in the reduc- 

 tion of the observations has been performed, and the 

 results given to the scientific public. 



The chief work of the year was the continuation of the 

 general re-observation of the stars in the Ccelum Australe 

 Stelliferutn of Lacaille, attention in 1875 having been 

 directed to those stars lying between 145° and 155° of 

 north polar distance at the present epoch, all of which 

 appear to have been observed, usually three times in both 

 elements, together with a number of other stars in the 

 same zone, which, though not generally much below the 

 seventh magnitude, were not observed by Lacaille. Mr. 

 Stone mentions that stars within limits of N.P.D 135°- 

 145° were observed in 1876, and stars between i25°-i35° 

 in 1877. 



Should it be deemed advisable shortly to form another 

 general catalogue of stars, similar to the British Associa- 

 tion Catalogue, say to stars of the seventh magnitude 

 inclusive, Mr. Stone's recent volumes will be of the 

 utmost value in extending the precision now attainable 

 for such stars in the northern hemisphere to the southern 

 heavens, not only as regards positions for the present 

 epoch, but in the determination of proper motions of a 

 considerable number of stars by comparison with Taylor's 

 catalogues, which have not yet been systematically ex- 

 amined for that purpose. And we will take this oppor- 

 tunity of expressing the hope that if another catalogue 

 like the B.A.C. should be undertaken, the time, labour, 

 and expense involved in the preparation of so-called star- 

 constants may be avoided, and attention paid instead to 

 a more general and systematic investigation of proper 

 motions, which, it can hardly be doubted, must lead to 

 results of great interest and importance. 



The Total Solar Eclipse of July 29. — It was 

 mentioned in Nature last week that facilities would be 

 afforded to intending observers of this phenomenon near 

 Denver, Colorado, one of the chief places included in 

 the belt of totaUty in the United States, and situated on 

 the Pacific line of railway. By the elements of the 

 Nautical Almanac the track of central eclipse appears to 

 pass about twenty-five miles south of Denver, assuming 

 its longitude from Greenwich to be 7h. cm. 20s. W,, and 

 latitude 39° 48', and at Denver the total phase commences 

 at 3h. 28m. 14s. local mean time, and continues 2m. 45s., 

 with the sun at an altitude of 42° ; the circumstances by 

 the elements of the American ephemeris are almost iden- 

 tical, as indeed was to be expected seeing that the moon's 

 place in the latter work differs from her place in the 

 Nautical Almanac by only -f 3-"4in R.A. and -f i"'o in 

 decl. and the sun's place by - v"i in R.A. and + o"-3 in 



dec!., while the semi-diameters employed are each less by 

 about 2". In the American ephemeris the lunar tables of 

 Peirce and the solar tables of Hansen are employed. 



The northern and southern limits of totality in the 

 eclipse of July 29, with the duration of total phase upon 

 the central line, for nearly the whole track across the 

 North American continent will be found at p. 400 of the 

 Nautical Almanac for 1878. 



CHEMICAL NOTES 



Temperature of Flames.— In the Gazetta chimica 

 Italiana an account is given by F. Rosetti of some ex- 

 periments on the above subject. To examine the tem- 

 peratures he employs a thermo-electric element consisting 

 of an iron and a platinum wire wound closely together 

 and connected with a galvanometer. This latter was 

 graduated to various temperatures by observing the devia- 

 tion consequent on bringing the element in contact with 

 a copper cylinder heated to known temperatures ; these 

 being determined by introducing the cylinder into a 

 calorimeter. With such an arrangement he has investi- 

 gated the flame of a Bunsen's burner, finding that in the 

 same horizontal strata there were but slight alterations in 

 the temperature, with the exception of the dark interior 

 portion. Thus, where the external envelope showed 

 i)3So°> the violet portion Jof the flame was 1,250°, the 

 blue 1 ,200°, but the internal portion much lower, its tem- 

 perature gradually decreasing from the base of the flame 

 upwards. A flame produced by the combustion of a 

 mixture of two volumes of illuminating gas and three 

 volumes of carbonic^oxide, showed a temperature of 

 1,000°. 



Starch in Plants.— Botanists have hitherto held that 

 all the starch in the chlorophyll cells of the leaves of 

 plants is a product of the direct assimilation of carbon 

 dioxide and water, basing this belief on the fact that the 

 starch in these cells disappears when the plants are 

 deprived of the power of assimilating carbon dioxide, but 

 reappears on their exposure to light in an atmosphere 

 containing that substance. Prof. Bohn, of Vienna, in a 

 recent number of the Deut. chem. Ber.; throws some 

 doubt on this conclusion by experiments he has made on 

 the leaves of the scarlet runner. His results show that 

 if the primordial leaves of this plant are shaded from light, 

 the starch at first entirely disappears ; after a few weeks, 

 however, the chlorophyll cells of these shaded leaves 

 show almost as high a percentage of starch as the parts 

 of the plant which have been exposed to light. These 

 observations demonstrate, therefore, that starch can be 

 formed in the leaves from matter which has already been 

 assimilated, and has entered into the leaf after its 

 removal from the sunlight. 



SiPYLiTE, a new Mineral Containing Niobium,-— 

 Mr. Mallett has found this mineral among some quantities 

 of allanite from Amhurst county, Virginia. A few crystals 

 have been obtained, but as they are of rather imperfect 

 nature the measurement of the angles has only been 

 attempted in a rough manner. The mineral in the mass 

 was of a brownish black nature, but in thin plates it 

 exhibited a reddish-brown colour, and possesses a pseudo- 

 metallic lustre. The hardness is estimated at about 6, 

 and the specific gravity as equal to 4'89. From the re- 

 sults of analyses Mr. Mallet considers that placing together 

 the acid oxides of niobium, tantalum, tungsten, tin, 

 and zirconium, reducing the basic oxides to equivalent * 

 amounts of dyad oxides, and eliminating the water, the 

 following ratio may be obtained : — R"0 : M^gOg = 221 : 

 100, leading to the formula R"3M^308 . ^'^^^0^, that 

 is a single group of orthoniobate associated with four of 

 pyroniobate. If the water be taken into account in the 

 calculation and considered basic, then placing it on the 

 same footing as the dyad oxides, we should have the 



