1895.] MICROSCOPICAL JOURNAL. 377 



front of the base upward, a heavy iron bar forming one 

 of the short tripod supports, is fitted beneath the front 

 of the board, entirely obviating any such danger. The 

 })Iatform itself is of sufficient length to carry microscope, 

 lamp and bull's-eye condensing lens on stand, the added 

 weight of which serves also to give increased steadiness 

 to the whole apparatus. 



It is not within the scope of this already too lengthy 

 paper to say anything in regard to the making of a neg- 

 ative from a microscopic object. This must be left to 

 another occasion. But it may not be amiss to glance for 

 a moment at the source of light for making the exposures. 

 Diffused daylight, reflected from the mirror is probably 

 the most generally useful illuminant and the various po- 

 sitions in which the " Autograph " camera can be placed 

 give the day worker many advantages in its use. But 

 most of us have perforce to do our work by night with ar- 

 tificial light. Fortunately there are many of these, some 

 one or more of which are available to every one. The 

 lime light (best of all in the opinion of many) the Elec- 

 tric arc, the Welsbach gas burner and the humble omni- 

 present petroleum lamp are all good, varying mainly in 

 the diftering lengths of exposure required with each. 

 And finally we have the new Acetylene gas lamp, which 

 places in the hands of every worker the ideal light for 

 Photo-Micrography. 



A few words as to the value of the '^ Autograph " cam- 

 era in copying, and in making lantern slides by enlarge- 

 ment or reduction, and I will tax your patience no longer. 



For both these purposes, the camera fitted with a pho- 

 tographic lens of not more than nine inches focal length 

 and inclined at the angle of 45° is to be placed near a 

 window audits base cleared of the microscope, lamp, etc. 

 A carrying frame with its upper surface parallel with the 

 camera front takes their place upon the platform, to which 



