8G 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



image of the field, as seen on the drawing-paper, should be visible through 

 the neutral tint glass. 



Lastly, the tube-fitting of the camera should bo made as long as 

 possible, thus allowing of the camera being moved closer to or farther 

 from the eye-piece, and enabling the best position to be obtained for 

 use with eye-pieces of different powers and fucal lengths. 



Electric Focus Lamp for the Microscope. — Fig. G, on the foregoing 

 page, illustrates Edison and Swan Company's focus lamp recommended 

 by Mr. C. F. Rousselet for use with the Microscope, and described by 

 him in the number of this Journal for December 1900, p. 741. The lamp 

 should be of 8 candle-power, and mounted with the usual brass collar 

 terminal for use with the ordinary bayonet-joint holder, like the ordinary 

 electric lamp. Mr. Rousselet recommends that the standard to carry 

 the lamp should have an arm to move up and down, similar to the 

 ordinary Microscope lamp, and the arm a knuckle-joint in order to be 

 able to adjust the lamp in an upright or horizontal position, or at any 

 intermediate angle, as may bo desired. A second similar arm may bo 

 provided to carry a bull's-eye condenser. 



Resolution of Striae.* — Dr. R. H. Ward, of Troy, N.Y., recommends 

 for the resolution of stria?, &c, the old method of obtaining oblique 



light by the decentralisation of the substage 

 F in - '• condenser. 



(4) Photomicrography. 



Photography in Botany and in Horti- 

 culture, f — Messrs. Waugh and Macfarland 

 consider the importance of the camera as 

 second only to the Microscope for the bot- 

 anist ; while for the horticulturist they would 

 give it the first place. 



The essentials are a vertical camera and 

 a horizontal shelf. Figs. 7 and 8 show two 

 modes of attaining the result. The former 

 is in use at the Vermont Experiment Station, 

 and is more of an out-of-door form ; the 

 Litter is used at the Mount Pleasant Printery, 

 and is more intended for the studio. 



The advantages are : (1) Nearly all 

 trouble in arranging the object is avoided, as 

 the specimen has merelv to be placed on the 

 shelf; in the case of a fruit which sometimes 

 does not readily assume stable equilibrium, 

 a rubber hose-washer forms a useful holder, and a supply of them should 

 be always at hand. (2) A sheet of paper of any tint can be placed under 

 the object so as to form any background desired. (3) Shadows arc 

 avoided. (4) The making of photographs exactly to the size is facili- 

 tated. 



A photograph the same size as the object is most desirable ; to obtain 



* Tians. Amer. Micr. Sac, 11)00. p. 111. 



t Bot. Gazette, xxx. (1900) j>p. 204-C (2 figs.). 



