March 21, 1895] 



NATURE 



491 



of entomologists, does not amount to many times that which 

 ' the United States Government grants. The results have thus 

 added greatly to the pioductive wealth of the world, and this 

 fact alone should be sufficient to lead our own Government to a 

 more generous recognition of work in economic entomology. 



Several German periodicals have published an account of 

 a remarkable balloon ascent made in the " Phoenix " by Dr. 

 A. Berson, on December 4 last. The balloon was inflated 

 with 70,600 feet of hydrogen, and ascended from Stassfurt 

 ( Prussia) in the morning, taking a north-westerly direction, the 

 weather at the time being somewhat misty. The temperature 

 at first increased up to a considerable height ; at 4900 feet the 

 thermometer stood at 41', and at 16,400 feet it read o , with a 

 very dry air. At noon, an hour and half after starting, a height 

 of 22,150 feet was reached, and the lliermometer fell to -20'. 

 At this time Dr. Berson began the artificial inhalation of oxy- 

 gen, with excellent results. At about 29. 500 feet the balloon 

 passed through a veil-like stratum of cirrus clouds; these did 

 not consist of ice crystals, but of perfectly formed flakes of 

 snow. About two and a half hours after starting, a height of 

 about 31,500 feet had been reached, the thermometer dropped 

 to -54°, and indicated only -11° in the sun's rays; at this 

 height Dr. Berson, being alone, thought it prudent to com- 

 mence the descent. At 4600 feet the highest temperature was 

 recorded, viz. 43°, and between this point and the earth it 

 dropped to about 34 : The ascent occupied 3 hours, and the 

 descent 2h. 20m., the balloon having travelled 1S6 miles, 

 notwithstanding that the wind was almost calm on the surface 

 of the earth. Dr. Berson obtained observations at a greater 

 altitude than they had before been made ; in Mr. Glaisher's 

 celebrated ascent of September 5, 1862, the last actual obser- 

 vation was at 29,000 feet, although it is supposed that the 

 balloon rose at least 7000 feet higher. The above particulars 

 are taken from an account given in the American Engineer for 

 this month. 



About three years ago, the Botanic-Garden at Cape Town 

 was transformed into a town garden supported by municipal 

 rates. A similar change has lately taken place at King 

 William's Town, in the eastern province of the colony. The 

 k'e-Ji' Bullelin for March rightly condemns these changes, and 

 the perfunctory manner in which botanic gardens in South Africa 

 have generally been treated. It points out that, at the present 

 m oment. Cape Colony is the only important British possession 

 w bich does not possess a fully-equipped botanical institution. 

 It is true it possesses a fine colonial herbarium, undei the com- 

 petent charge of Prof. MacOwan, and an agricultural depart- 

 ment which he efficiently advises on botanical subjects. But 

 b eyond this it has no central authority dealing with the practical 

 aspects of the science of botany, and no gardens under 

 technical control where careful experimental cultivation could 

 be carried on, or where special seeds and plants could be ob- 

 tained for starting new industries. This condition of alTairs, 

 the Bulletin holds, is scarcely credible to a large and wealthy 

 community like that at the Cape. Something more than an 

 ornamental garden, dotted here and there, is required in South 

 Africa. A central establishment in the neighbourhood of Cape 

 Town, devoted to the scientific study and experimental cultiva- 

 tion of plants, fully equipped to discharge its studies as a 

 national institution on the lines of Kew, would alone be worthy 

 of the future of South Africa. The flora of this part of the 

 world is one of extreme interest. It deserves to be carefully 

 and exhaustively studied, and numerous plants, now in danger 

 of becoming extinct, should be preserved in some central spot 

 for the observation of students. Of the economic influences of 

 such a central institution it is needless to enlarge. There are 

 hundreds of problems connected with the cultivation of in- 

 NO. 1325, VOL. 51] 



dustrial plants in South Africa awaiting solution, and these 

 could only be dealt with at an institution specially devoted to 

 scientific research, where careful trials could be conducted ex- 

 tending over many years. 



In a recent publication by Dr. L. A. Bauer, entitled "Beit- 

 raege zur Kenntniss des Wesens der Saccular Variation des 

 Erdmagnetismus " (Inaug. Diss., University of Berlin), some 

 interesting and important contributions to our knowledge of that 

 enigmatical phenomenon of terrestrial magnetism^the secular 

 variation — have been made. The author has constructed the 

 actual curve described in the course of centuries by the north 

 end of a " free magnetic needle " at various stations (24) dis- 

 tributed over the globe. The result has been the establishment 

 of a law governing the direction of the curve, which the author 

 claims is the first law that has been established thus far with 

 regard to the secular variation as applying to the whole earth. 

 This law may be expressed as follows: — The north end of a 

 freely suspended magnetic needle, as viewed from the point of 

 suspension of the needle, moves, in consequence of the secular 

 variation of terrestrial magnetism on the entire earth, in the 

 direction of the hands of a watch. With regard to the period. 

 Dr. Bauer believes that it has not yet been proved that the earth 

 actually possesses a common secular variation period. The 

 only way he thinks it possible to deduce a common period is by 

 the supposition that the curve described by the magnetic needle 

 is not a single closed one, but consists of loops. Indications of 

 such loops, he says, make themselves apparent at various 

 stations. A comparison is also drawn between the secular 

 variation and the momentary distribution of terrestrial magnet- 

 ism. A secular wave is followed around the earth with the aid 

 of the projected curves. It would appear as though a con- 

 tinuation of the secular curve is obtained by going around the 

 earth eastwardly. The fact thus revealed, the author says, 

 would have, as a direct consequence, that if a survey be made 

 along a parallel of latitude in an easterly direction, a similar 

 motion of the magnetic needle would be encountered as in the 

 case of the secular variation. Dr. Bauer has carried oat this idea 

 for three epochs, viz. 1780, 1829, and 18S5, and along several 

 parallels of latitude. The curves described by the needle are 

 projected and given on a special plate. It has been found that 

 in every case the north end of the needle, as observed from the 

 centre of the needle, moves clockwise. Furthermore, by a 

 comparison of both sets of curves — the secular and the momen- 

 tary — it would appear as though they are subject to similar 

 laws. 



The method adopted in thePhysikalisch-TechnischeReichs- 

 anstalt for turning true spheres is described by Herr von 

 Liechtenstein in the /.citichrift fiir InstrunientenkuniU. Three 

 grinding cylinders, the diameter of which is less than that of 

 the sphere, are mounted in a lathe, two of them being carried 

 by one head and one by the other. They are disposed at angles 

 of 120° to each other in a horizontal plane, and grasp the sphere 

 between them. Their rotation produces a perfectly irregular 

 motion of the sphere, and between the three cylinders it is 

 ground to an extraordinary truth of figure. Iron and steel 

 spheres of 25 mm. diameter thus produced showed errors of 

 diameter not exceeding 0'OOI5 mm. 



In the yearly report of the Russian Geographical Society, we 

 notice that M. Roborovsky, chief of the Tibet expedition, has 

 m.ide a careful survey of the Lukchun depression, the level of 

 which, as is known, lies below the level of the ocean. It appears 

 that the depression has a length of nearly too miles, and an 

 average width of 50 miles, and that its level is from 100 to 150 

 metres below the level of the sea. The desert which is situated 

 in the south of it was crossed in several directions, and M. 

 Roborovsky succeeded in obtaining no less than six speci- 



