and Laboratory Methods. 



1115 



screen is brought in position horizontally by sliding the lens and board, which 

 can be done by turning the milled head on the top of the camera. 



To make the exposure, place the object in its best position and focus 

 as sharply as possible. With the image in the proper place on the screen, fasten 

 front and rear of camera by means of the clamp screws at the side, run in the 

 plate-holder until it drops into the ^rsf groove. Set the camera in position, with 

 the reflector facing a northern sky, and make the first exposure. 



Figure 8. 



After the first exposure has been made the object has to be rotated. Upon 

 the pedestal will be found a graduated circle, divided into parts of five degrees 

 each, and also a pointer. The insect has now to be rotated one of the gradu- 

 ations (five degrees), from left to right, and then the image on the screen is 

 again placed in position, plate-holder is returned and run back as far as possible 

 until it drops into the second groove, the exposure repeated for the other end of 

 the plate. By revolving the object in the direction just mentioned, the negative 

 itself is made stereoscopic, and can be placed in the stereoscope and examined 

 to see if it is perfect. 



The New York Botanical Garden. 



" The advancement of botanical science and knowledge and the prosecution 

 of original researches therein and kindred subjects " are some of the primary 

 purposes set forth in the charter of the New York Botanical Garden, and it may 

 be of interest to botanists and biologists in general to note to what extent and 

 in what manner research work may be prosecuted in this institution. 



A prerequisite to all successful botanical work consists in the possession of 

 typical specimens, and in experimental work it is important that normal con- 

 ditions of growth should be available, as well as facilities for producing and 

 controlling experimental factors. 



