SGS SCIENTIFIC RECORD FOR 1883. 



rotation. This case is entirely improbable, however, from the position 

 of the visible Milky Way and it is much more to be feared that h will 

 remain appreciable. For if we put accordingly Q — 286°i = G2£° wo 

 have (<•/' = lunar-solar— and A = planetary precession): 

 /= 0.92 if> + 0.4G dl - A = (>/; + h dl) cos go - A 

 <j = 0.40 tf> + 0.15 dl . = (tf> + \ dl) sin co — 0.05 dl 

 h = - 0.S7 dl 



and we obtain ; hereby from /and g, with only a very unimportant dif- 

 ference, the precession with an error of £ dl merely. A value of h 

 exceeding 4" or 5" a century is moreover exceedingly improbable for 

 those stars used by Bessel and Struvein the determination of precession, 

 and the limits could be yet more closely drawn if the separation of the 

 unknown quantities had not been made much more difficult by those 

 quantities depending on the motions of the sun, by the systematic 

 errors of the catalogues, and by the unfavorable distribution of the 

 stars (a lack of such having tolerably large negative tang.-<J and sin 8). 



"A secular rotation amounting to several seconds seems, aside from 

 the smaller influence of the terms marked F, G, H, to be more readily 

 derived from the fainter stars than iroin the brighter ones (if for no 

 other reason than) because they are available in very large numbers. 



"The above equations, however, will not serve to completely separate 

 the quantities //' and dl unless at least one of the quantities go and i is 

 known from another source. For this purpose star-gauges, and in fact 

 all more thorough and fundamental astronomical work would, in the 

 present state of our knowledge, be of the greatest value. This method 

 of determining both quantities affords us in the determination of ip and 

 dl from/, g, aud h a check which is fully as valuable as the independent 

 determination of g and h from both the co ordinates of stars." 



The reviewer does not attempt to carry out in detail all these inves- 

 tigations. He is convinced, however, that the hypotheses which must 

 necessarily be assumed in doing this are not of so indefinite and arbi- 

 trary a character, but that the treatment of the precession problem in 

 the manner herein sketched will result in a closer approach to the true 

 method than do those which have been hereto employed. 



Even the possible proof that the component of rotation h does not 

 exist even down to the 8 m and 9 m would be of great value. The prac- 

 tical difficulties appear greater, perhaps, than they really are ; and will 

 be substantially diminished after the completion of the zone work of 

 the Astronomische Gesellschaft, as Dr. Dreyer has particularly pointed 

 out. 



Untenmchiingen iiber die Priicessionsconstante auf Grund dcr Stern- 

 cataloge von Lalande und Schjellerup. Inaugural-Dissertation von F. 

 Bolte.* — In the preceding abstract the views of Professor Schonfeld 

 as to the relations between the precession, the motion of the solar 



* Bonn, 1883 (28 pp. 8vo). 



