158 THE AMERICAN MONTHLY [July, 



been added, and a slip of copper coil introduced, the arsenic will be 

 deposited as an iron-grey coating. Remove the slip, wash well with 

 water (alcohol and ether if any fatty matter is present), and gently heat 

 in a tube when the characteristic crystals will again be produced. 

 Copper and tube must be well dried. Cautions in this test are, not to 

 employ too large surface of copper and not to remove the copper from 

 the solution too soon. 



When examined with ;^-inch objective these crystals can be seen and 

 recognized by their shape up to jj^l ^fJy of an inch in diameter. Other 

 substances will yield a deposit on copper, viz : Antimony, Bismuth, 

 and Mercury. The volatility of the arsenic and the character of the 

 crystal will settle the question. 



Brief History of the San Francisco Microscopical Society. 



By henry G. hanks, 



SAN FKANCISCO, CAL. 



The San Francisco Microscopical Society originated in the Academy 

 of Sciences. Hiram G. Bloomer and Henry G. Hanks, both active 

 members of that society, realizing the importance of the use of the mi- 

 croscope in their especial studies, botany and geology, proposed form- 

 ing a microscopical section of the academy. The plan not according 

 with the views of other members, it was decided to form a new and 

 independent society. A number of meetings were held at 649 Clay 

 street, and on the evening of June 4, 1870, the San Francisco Micro- 

 scopical Society was organized, a constitution and by-laws adopted, and 

 officers elected. 



The officers for the first year were : J. B. Trask, M. D., President; 

 Gregory Yale, Vice-President ; Henry C. Hyde, Recording Secretary ; 

 Henry G. Hanks, Corresponding Secretary, and Emile Neustadt, Treas- 

 urer. Henry C. Hyde and Henry G. Hanks are still members of the 

 society. 



For want of funds and for other reasons no considerable advance was 

 made. Having no adequate apparatus, interest after a few months 

 began to wane, and before the expiration of a year meetings were dis- 

 continued and the society practically ceased to exist. There were some 

 members who were not discouraged, and comparing views and discus- 

 sing the causes which lead to dissolution, resolved on a new organiza- 

 tion, and the result was the present society. 



The proceedings of the original society have not been preserved. 

 An event transpired during its existence worthy of record, which is 

 remembered with pleasure by the older members. Early in- 1871 Joseph 

 Beck, the eminent London optician, visited San Francisco for the first 

 time, and March 14 he gave a reception to the members at the Cos- 

 mopolitan Hotel. On this occasion he exhibited a magnificent binocu- 

 lar microscope of aluminium, with all accessories complete. Besides 

 the rare and interesting objects brought with him, he showed others 

 from the society's collection, among which were individual gold crystals 

 from Owen's Valley, metacinnabaiite (then recently discovered) , sili- 

 cified wood, platinum, and diamond sands from the coast of Oregon. 

 The exhibition was a revelation to the society, and the fledglings who 



