156 



SCIENCE. 



[Vol. IV., No. 81. 



Saturn's satellites in 1875, upon taking charge of the 

 great Washington refractor. This ignorance of the 

 exact value of the mean motion is especially unfortu- 

 nate in the case of Hyperion, from the fact that 

 four times this motion very nearly equals three times 

 that of its disturbing giant neighbor, Titan; in which 

 case the perturbations become very large, or, in case 

 this relation is an exact one, the theory of their mo- 

 tions is very greatly modified. Until, then, the lapse 

 of time and continued observation shall show how 

 much the quantity 4n— on' differs from zero, it is Pro- 

 fessor Hall's opinion that it will be useless to attempt 

 the complete theory of Hyperion's motion. 



To show something of the rapid changes in the 

 elements of the orbit due to the great perturbations 

 going on, Professor Hall has discussed the observa- 

 tions of each year separately, assuming a value of the 

 inclination and longitude of node determined before- 

 hand from his earlier observations, — which quantities 

 are very little disturbed, — and by least squares has 

 deduced for each year, including Lassel's 1852 obser- 

 vations, values of the semi-major axis, eccentricity, 

 and longitude of peri-Saturn ium for Hyperion. The 

 most remarkable feature of the results is the rapid 

 retrograde motion of the peri-Saturnium, amounting 

 to about 20° per year for the epoch 1875-77, but ap- 

 parently diminishing quite rapidly. This motion is 

 comparable with the rapid retrogression of the moon's 

 nodes ; but it would seem to be rather irregular, unless 

 the printed annual values of P are liable to consider- 

 able uncertainty. Professor Hall calls attention to 

 the desirability and importance of re-reducing Lassel's 

 observations, and publishing them more in detail." 



— Insecten-horse is the title of an advertising fort- 

 nightly sheet just started in Leipzig for the benefit 

 of collectors, dealers, and amateurs in entomology. 

 The first number, composed of four quarto pages, 

 contains a surprising variety and number of objects 

 for sale. 



— A blue grotto, similar to that of Capri, has been 

 found on the Island of Busi, off the coast of Dalma- 

 tia. It is formed by three connected grottos, which 

 can only be approached from the sea. It is highly 

 vaulted, and is only lighted through an opening under 

 the sea; this causing the glorious reflected blue light. 



— It is proposed to hold a special American exhi- 

 bition in London in May, 1886, at which the products, 

 manufactures, and varied phases of life in the United 

 States, will be represented. 



— We learn from Nature that Prof. R. S. Ball has 

 accepted an invitation from the Lowell institute, 

 Boston, to give a course of six lectures on ' Chapters 

 in modern astronomy' next October. 



— A German expedition has been despatched to 

 Cape Town in the corvette Elizabeth. It is fitted out 

 by the firm of Liideritz of Bremen, and will after- 

 wards proceed to Angra Pequena. The leader of the 

 expedition is Lieut. Siegmund Israels, a Hamburger, 

 who served in the English army during the Ashantee 

 war. An engineer has been engaged from Diissel- 

 dorf, who will use his experience in the service of a 

 Westphalian firm of iron founders. 



— We learn from Germany, that the Italian geolo- 

 gists have written to the president of the interna- 

 tional geological congress at Berlin, asking that the 

 intended meeting of September next be postponed 

 to another year, on account of the cholera, and the 

 quarantine imposed at the boundary of several king- 

 doms in Europe. Later information is, that the con- 

 gress will be postponed to September, 1885, not only 

 on account of the cholera, but also on account of the 

 number of members drawn off to America by the 

 meeting of the British association. It is also stated 

 that the reports of several of the committees could 

 not be ready this year. 



— A hypsometric chart of European Russia, pre- 

 pared by Gen. Tillo, has been published at the 

 expense of the ministry of public works. The alti- 

 tudes of more than 18,000 points are indicated on this 

 chart, of which 12,000 were trigonometrically fixed, 

 4,000 determined by levelling, and only 400 rest upon 

 barometric observations. More than 1,500 mean 

 heights for the level of the water at points on vari- 

 ous rivers are also included. The chart is accom- 

 panied by an explanatory memoir. 



— Prof. George H. Darwin of Trinity college, 

 Cambridge, is now in this country, and has lately 

 married a Philadelphia lady, Miss Maud Dupuy. 

 He returns to England after the conclusion of the 

 meeting of the British association for the advance- 

 ment of science at Montreal. 



— Apropos of the distinction which has lately 

 fallen to Prof essor Roscoe of Manchester, — a knight- 

 hood conferred by the queen in consideration of his 

 services in connection with the technical education 

 commission, — the London Academy calls to mind 

 the fact that he affords a fine example of the union of 

 the qualities needed by the successful investigator 

 with those of a good man of business; and that his 

 popular sympathies have won him the warm regard 

 of the Lancashire workingmen, among whom the 

 study of science is more common than might be 

 supposed. 



— According to the Personal-verzeichniss der Uni- 

 versitdt Leipzig fur das summer semester, 18S4, there 

 are, in all, 3,160 students at the university, of whom 

 608 are studying medicine, 99 pharmacy, 232 natural 

 science (naturwissenschaften), and 137 mathematics. 

 There are 41 Americans at the university, of whom 

 7 are studying science. Three of the whole number 

 of students were matriculated as early as 1878, and 

 33 more in 1879. Dr. Caspar Rene Gregory of Phila- 

 delphia has just been appointed privat-docent in the 

 theological faculty in recognition of his researches in 

 textual criticism. 



— The following societies will be represented at 

 Philadelphia, in addition to those already mentioned 

 (Science, iv. 140): Geological survey of India, Theo. 

 Hughes Hughes (deputy superintendent); Belfast 

 natural-history and philosophical society, Messrs. 

 James Musgrave, Henry Musgrave; Linnean soci- 

 ety, Messrs. John Ball, A. W. Bennett, W. Carru- 

 thers, C. Delaune, Howard Saunders, and Dr. James 

 Murie. 



