Iv 



Henry Shaw, might he made to contrihute to a useful advance- 

 ment of the science of botany. 



Dr. Hinrichs presented a paper on "The Determination of the 

 Magnetic Rotary Polarization of Compounds from their Chemi- 

 cal Formula)." 



A paper by Dr. H. H. Behr, of San Francisco, entitled 

 "Some Biological Peculiarities of the Phylloxera, and a Method 

 to Utilize them for the Protection of Vineyards," was read by 

 Dr. Trelease. 



November i6, 1891. 



President Nipher in the chair ; nine members present, one 

 visitor. 



Prof. Nipher exhibited drawings for Electric Railway Power 

 Stations of the Edison and Thomson -Houston systems, and ex- 

 plained the arrangement and uses of the various machinery em- 

 ployed, and the manner of its operation. 



Mr. Winslow made some remarks on the progress of work in 

 the Geological Survey of the State. 



December *]tk, 1891. 



President Nipher In the chair ; fourteen members preesnt. 



A donation from Dr. Gustavus Hinrichs of a pamphlet enti- 

 tled "A Celestial Messenger, or Fiery Stones hurled from Heav- 

 en," being a reprint of a paper contributed by him to the Chape- 

 rone (St. Louis), and of a collection of "Six Notes de Chimie 

 Moleculaire," contributed by him to the Cojnptes Rendus (Paris), 

 T. cxii. and cxiii. 1891, was acknowledged by a vote of thanks. 



Prof. Pritchett gave the results of the discussion of observations 

 made during the past winter for the determination of the Rota- 

 tion Period of Jupiter. The object whose transits across the cen- 

 tre of the disc were observed was the well known "Red Spot" 

 which has been a permanent feature of the planet for 13 years. 



Fi'om 3 1 equations of condition there was found 



Rotation time ■= 9^ 55m 37? 37 -j- o? 38. 



This spot has been observed to rotate for some years past in 

 9'^ 55'" 42^ i and the result just given is particularly interesting as 

 v. — E 



