412 



SCIENCE. 



[Yol. V., No. 119. 



The uniformity and continuity of the system of ob- 

 servations make the results of much interest. Three 

 sentinels are on duty during the night, and each is 

 required to report, when relieved, whether he has 

 seen any auroral light during the night, and, if not, 

 whether the sky has been sufficiently clear to per- 

 mit any to be visible. At the end of the year the 

 number of auroras, taking the mean result from 

 the three observers, are added, and also the number 

 of nights on which auroras could not have been 

 seen owing to clouds. The probable number for the 

 year is obtained by increasing the observed number 

 in the same ratio as that of the cloudy nights to the 

 clear nights. The results are shown in the following 

 table. The last column of the table gives the aver- 

 age number of sun-spots as observed by Prof. D. P. 

 Todd. 



Summary of auroral records for fifteen years. 





Clear sky. 



Cloudy sky. 





Aver- 











Total 

 for 



age 



Year. 











no. of 





Nights. 



Observed 

 auroras. 



Nights. 



Probable 

 auroras. 



year. 



sun- 

 spots. 



1870 . . 



184 



50 



150 



41 



99 





1871 . . 



211 



60 



154 



44 



104 



- 



1872 . . 



234 



60 



132 



34 



94 



- 



1873 . . 



214 



54 



151 



38 



92 



- 



1874 . . 



190 



18 



175 



17 



35 



- 



1875 . . 



189 



14 



176 



13 



27 



_ 



1876 . . 



195 



9 



171 



8 



17 



- 



1877 . . 



191 



7 



174 



6 



13 



2.6 



1878 . . 



185 



2 



180 



2 



4 



2.2 



1879 . . 



204 



9 



161 



7 



16 



2.0 



1880 . . 



216 



13 



150 



9 



22 



14.3 



1881 . . 



191 



23 



174 



21 



44 



26.7 



1882 . . 



201 



55 



164 



44 



99 



28.3 



1883 . . 



215 



24 



150 



17 



41 



27.4 



1884 . . 



180 



12 



186 



12 



24 



38.0 



— According to the explorer, Col. Prjevalski, 

 Thibet appears to be a paradise for gold-diggers. In 

 the letter in which he describes the discovery of 

 the sources of the Yellow River (the Hoang-ho), he 

 writes: In the neighborhood of the southern slope 

 of the Burchan-Budda, we met with about thirty 

 friendly Tauguts, who were employed in gold-wash- 

 ing. The whole of northern Thibet seems very rich 

 in gold. At the gold-washing place we visited, the 

 Tauguts were digging the gravel containing the gold 

 from a depth of only from about one to two feet; 

 and, though the gold-washing was only done in the 

 most primitive way, the Tauguts showed us whole 

 handfuls of gold in large pieces, of which none were 

 smaller than a pea. Doubtless, careful working of 

 the gold-washing process would yield enormous treas- 

 ures. It seems to me, too, that the prophecy is not 

 too bold, that Thibet, in time, will prove a second 

 California. 



— Dr. Aurel Schulze, the son of a German colonist 

 in Natal, has recently returned from a successful 

 journey into the interior. He advanced up the Ku- 

 ando, or Chobe, for a considerable distance, and pro- 

 ceeded thence to the Kubango, where his farther 

 progress to the west coast was stopped through the 

 hostile attitude of the natives. He returned to Natal 

 by way of lake Ngami and the Transvaal. 



— A. Riche has presented a report to the Council of 

 hygiene of the department of the Seine, in which he 

 states that vaseline should not be used for alimen- 

 tary purposes, as it is injurious to health. This sub- 

 stance has been recommended for use in pastry, as it 

 is said to show no tendency to become rancid. 



— The Academie des sciences offers for this and 

 the three following years a medal of the value of 

 three thousand francs, for some important improve- 

 ment in the theory of the electric transmission of 

 work. The Bordin prize of three thousand francs is 

 also to be given for the best memoir on the origin of 

 atmospheric electricity, and the causes of the great 

 development of electrical phenomena in storm-clouds; 

 this to be sent in before the 1st of June next, the 

 other before the 1st of June, 1886. 



— Tea-cultivation is making some progress in Italy. 

 In the province of Novara a plantation is reported to 

 be doing well; and at the agricultural show at Mes- 

 sina, in 1882, Signor d'Amico exhibited a hundred 

 plants three years old, that had been grown in the 

 province of Messina. The Italian government has 

 sent to Japan for a supply of plants. 



— The prize offered by the Societe d' encourage- 

 ment pour l'industrie nationale, of forty pounds, for 

 the discovery of ' a new alloy useful in the arts,' has 

 been aw arded to P. Manhes, on account of his discov- 

 ery of the value of an alloy of copper and manganese 

 for improving the quality of commercial copper. 

 Manhes prepares an alloy of seventy-five per cent 

 copper, and twenty-five per cent manganese, and adds 

 it in small quantities to the molten copper after refin- 

 ing and just before casting, stirring the bath of metal 

 at the same time. The manganese of the alloy is 

 stated to immediately combine with the oxygen of 

 the dissolved cuprous oxide, forming a manganiferous 

 slag which is easily removed. The operation is cheap, 

 and very much improves the quality of the copper so 

 treated. Also several of the principal alloys of cop- 

 per, bronze, gun-metal, brass, are of superior quality 

 when prepared with copper purified in this manner; 

 and copper so treated is more slowly acted upon by 

 sea-water. 



— Obrecht published, in a recent number of the 

 Comptes rendus, his result for the solar parallax as de- 

 rived from measures of the photographs of the tran- 

 sit of Venus of 1874, obtained by the astronomers of 

 the French expeditions. The value found is 8.80", 

 but it is not final, having still to be corrected for 

 some elements in the calculation whose precise value 

 is as yet unknown. A few years ago, Professor Todd, 

 in a similar way, obtained a preliminary result from 

 the American photographs of the same transit, which 

 was 8.88" for the solar parallax. 



— ' The sun,' by Rev. Thomas W. Webb (New 

 York, Industrial publication company, 1885), is ' a 

 familiar description of the sun's phenomena.' It is 

 after the style of the scientific primers, and gives in 

 seventy-seven small pages of coarse type a clear idea 

 of how the distance of the earth from the sun is de- 

 termined, and of what is going on upon the sun's 

 surface. 



