132 SUMMARY OF CUBRENT RESEARCHES RELATING TO 



claimed that the lamp " is the only one with practically no heat ; it 

 gives a delightfully soft and steady light, capable of great variation 



Fig. 17. 



Fig. 18. 



in intensity, and far less tiring to the eyes than ordinary reflected 

 light." 



The lamp can also be carried on a swinging tail-piece, after the 

 plan introduced by Mr. B. Bausch.* 



Bulloch's Cobweb Micrometer.f — A form of cobweb micrometer 

 has been introduced by Mr. W. H. Bulloch, in which in addition to 

 the movement of one set of lines with the micrometer screw, another 

 screw, worked with a milled head on the other side of the instrument, 

 moves both sets of lines together, so that it is possible to set the 

 graduated screw-head at zero for any particular measurement. This 

 is a very convenient as well as useful feature. 



Jung's Nose-piece Adapter. — Herr E. Jung has further improved 

 the Nachet-Thury form of adapter, t 



Fig. 19 is the adapter, and fig. 20 the ring which is screwed to 

 each objective. The adapter consists of a fixed inner cylinder which 

 screws into the body-tube, and a movable outer cylinder which is 

 kept pressed up towards the lower end of the body-tube by a strong 

 spiral spriQg. The bottom of the outer cylinder ends in a shoulder 

 which is cut away for about a third of its circumference, so as to 

 allow a ring and its objective to be slipped in when the cylinders 



* Appleton's Annua] Cyclopedia for 1884 (1885) p. 515 (1 fig.), 

 t Amer. Mon. Micr. Journ., vi. (1885) pp. 239-40. 

 X See this Journal, i. (1881) p. 661. 



