74 JOURNAL OF THE [October, 



Dead Black on Brass, and as Ground for Opaque 

 Mounts. — " The following process for preparing a dead black 

 surface on brass, for optical instruments, &c., is given by The 

 Locomotive : ' Take two grains of lamp-black, put it into any 

 smooth, shallow dish, such as a saucer or small butter-plate, add 

 a little gold size and thoroughly mix the two together. Just 

 enough gold size should be used to hold the lamp-black together. 

 About three drops of such size as may be had by dipping the 

 point of a lead pencil about half an inch into the gold size will be 

 found right for the above quantity of lamp-black ; it should be 

 added a drop at a time, however. After the lamp-black and size 

 are thoroughly mixed and worked, add twenty-four drops of 

 turpentine, and again mix and work. It is then ready for use. 

 Apply it thin with a camel's-hair brush, and when it is thoroughly 

 dry, the articles will have as fine a dead black as they did when 

 they came from the optician's hands.'" — The American Monthly 

 Microscopical Journal, Vol. VII. (1886), p. 37. 



Mr. W. C. Brittan, says {The Microscope, Vol. VI. (1886), p. 

 41, "This paint will also be found just the thing when a dead 

 black ground is required for opaque mounts." 



THE SAN FRANCISCO MICROSCOPICAL SOCIETY. 

 Meeting of August loth, 1887. 



A CALIFORNIA DIAMOND. 



professor hanks exhibits a rare gem found in AMADOR 



COUNTY. 



DISEASE germs AGAIN. INTERESTING FINDS AT THE SEASIDE. 



— SINGING SAND AT PESCADERO. 



The regular meeting of the San Francisco Microscopical So- 

 ciety was held in the society's rooms last evening, President 

 Wickson and a large number of members being present. In 

 the absence of Secretary Breckenfeld, Dr. C. P. Bates, of 

 Berkeley, acted as Secretary. 



Among donations to the cabinet were four slides of tubercu- 

 lar bacilli from Dr. Riehl, of Alameda, stained with different 

 preparations. William Norris presented a recently issued part 

 of Walker and Chase's series of " New and Rare Diatoms." 



