THE MICROSCOPE. 43 



fly were then photographed, Carbutt's' "J. C. B." plates, one 

 inch objective and an A eye-piece, the exposure given being 

 four and a half minutes. The lights were then extinguished and 

 the room lit by means of a red lantern. The plates were then 

 developed, the ladies and gentlemen present clustering around 

 the table to observe the process. After fixing and washing the 

 plates the gas was relit, and an examination showed that the 

 negatives were excellent, every detail being fully brought out. 



LAST evening there was quite a good attendance at the hall of 

 the Microscopical Society to listen to the address of Mr. John 

 Carbutt, of Philadelphia, upon the subject of Photo- Micrography. 

 A number of scientific gentlemen from Philadelphia were present. 

 Mr. Carbutt was one of the original members of the Illinois State 

 Microscopical Society, and, besides his interest in microscopy, he is 

 also well known throughout the country as a skillful photographer 

 and one who has done so much toward the popularizing of the dry- 

 plate process. In his lecture of last evening he spoke of the pecu- 

 liar adaptability of the dry plates to the wants of the microscopist, 

 on account of their extreme sensitiveness, and the fact that they can 

 be so easily manipulated even by those without previous experience. 

 The arrangement used for photographing was remarkable for its 

 simplicity and inexpensive character. It consisted of a board about 

 four feet long, with a ledge around it in which was fitted a sliding* 

 block to which the camera was attached, another for the microscope, 

 and one for the lantern, all adjusted to a proper height. The 

 microscope was attached to the camera by means of a rubber sleeve 

 connecting with a conical tube about fourteen inches long. The 

 lantern used was invented by the lecturer, and it is really a multum 

 in parvo, for, while it gives an unusually brilliant light for photo- 

 micrographic purposes, it at the same time furnishes a perfectly safe 

 light to develop plates by. 



With a two-inch Bausch & Lomb objective, and an exposure of 

 two minutes, a negative was taken from a spider's foot. With the 

 same objective, and an exposure of one minute and a quarter, one 

 was also taken from a sheep's tick, "B" plates being used in both 

 instances. The shorter exposure in the latter case was in conse- 

 quence of the object being much less dense and yellow. Upon being 



