1884.] 



MICEOSCOPICAL JOURNAL. 



207 



Griffith's New Turn-Table. 



Some time ago Mr. Griffith furnish- 

 ed us with a cut iUustrating his new 

 turn-table, but owing to our absence 

 from home it has been overlooked 

 until now. On page 126 will be 

 found an illustration of a simple form 

 which preceded this one. The cen- 

 tering device was somewhat different, 

 as well as the general construction. 



In the later form, which is repre- 

 sented in fig. 38, four pegs project 

 from the face, two near the margin, 

 which receive the corner of the slide, 

 and two situated on a central, circular 



drawings was often a quite laborious 

 task. The advent of the hektograph 

 was hailed by many as a deliverance 

 from this drudgery, but unfortunately 

 the hektograph has not proved what 

 was expected of it. There is a limit 

 to the number of copies it will give, 

 and it often fails to reproduce w^ell 

 fine details of the original drawing. 

 Still later photography has been 

 popularized, and now we enjoy the 

 ability to furnish any number of faith- 

 ful copies of a drawing, as well as the 

 more generally employed method of 

 photographing, by means of the mi- 

 croscope, the object itself. Although 



Fig. 28.— Griffith's New Turn-Table. 



piece which is flush with the surface. 

 This central piece turns freely, and is 

 acted upon by a concealed spring, 

 vs^hich causes the two pins to secure 

 the two sides of the slide and press it 

 against the outer marginal pegs. The 

 device is rather difficult to describe 

 clearly, but with the aid of the cut, 

 perhaps, the action will be made 

 clear. 



This turn-table may be obtained 

 either in the form shown in the cut, 

 with the iron hand-i;fst, or with the 

 revolving face on its pivot without the 

 rest, arranged to be screwed down to 

 the work-table. 



Multipljiug Drawings. 



In years past, when a naturalist or 

 microscopist came across a new or 

 unfamiliar form, and desired to send 

 sketches or camera drawings to his 

 correspondents, the copying of the 



an old process, it has but lately been 

 brought within the reach of all, and 

 is probably the best of all methods ; 

 but there are certain drawbacks even 

 to this process. Not every micro- 

 scopist has an outfit suitable for copy- 

 ing drawings by photography, and 

 most of them confine their work to 

 the production of j3hotographs from 

 the object itself, fi'equently having no 

 other lenses than those of their micro- 

 scope. 



In such cases it is soon found that 

 camera lucida drawings cannot be 

 wholly replaced by photographs. It 

 is frequently impossible to obtain 

 good photographs of structure that 

 can be clearly seen and drawn ; so it 

 often happens that the enthusiastic 

 amateur in microscopical photogra- 

 phy is much disappointed and per- 

 haps disgusted at having to go back 

 to camera lucida drawing when he 

 thought he had discarded it for good. 



