A. MATHEMATICS AND ASTRONOMY. 51 



PUBLICATIONS OF THE OBSERVATOEY OF BOTHKAMP. 



The private observatory of the Councilor von Biilow, at 

 Bothkamp, has just published its third volume of " Observa- 

 tions," under the editorship of Dr. O. Lohse, astronomer of 

 the observatory, and announces the speedy issue of a fourth 

 volume. The present volume is devoted to physical inves- 

 tigations on the nature of the sun's surface, to the registra- 

 tion of solar spots, and to the study of solar spots, faculs?, 

 etc. It is illustrated with plates of solar spots, etc., and we 

 note that one of the large spots drawn is the same already 

 studied by M. Trouvelot, a drawing of which was published 

 by Professor Winlock in the astronomical engravings from 

 Harvard College Observatory. The observatory of Herr von 

 Billow was the first one in Germany to be devoted solely to 

 celestial physics, and its great success may have had much 

 to do with the establishment of the Astrophysilialischen In- 

 stitute at Potsdam, by the Prussian government. 



THE SOLAR PARALLAX. 



Professor Galle, who has endeavored to calculate the solar 

 parallax from observations of the asteroid Flora, announced 

 as the final result of his computations 8.879" as deduced from 

 36 southern and 37 northern stars, the distribution of the 

 comparison stars being as favorable to an accurate result 

 as is possible. The greatest probable error that we can as- 

 cribe to this result is the one twenty-fifth of a second. But 

 it is very remarkable, if we divide his seventy-three equa- 

 tions into three sections of twenty-four or twenty-five obser- 

 vations each, that we deduce the following values, viz. : 8.96", 

 8.86", and 8.78". The whole computation will at some future 

 time be published in full; but Professor Galle states that he 

 has come to the conclusion that so accurate a result with so 

 small a probable error could only have been accomplished 

 by the kind co-operation of the observatories of the south- 

 ern hemisphere, and that even a still better approximation 

 can perhaps by this method be attained in the future. To 

 this end the observations should, if ever repeated, be made 

 with the largest telescopes, using the highest magnifying 

 powers. As constant errors can be eliminated by a prop- 

 er arrangement of the observations of the stars of compar- 



