1891.] MICROSCOPICAL JOURNAL. 89 



In all the processes heretofore described, the microscope has l)een 

 employed in conjunction with the camera, and beautiful results have 

 been attained. But in the method introduced now we discard the use 

 of the microscope entirely. Two advantaiijes are claimed for this. 

 First, the field of view is only limited by the size of the sensitive plate 

 employed, a great range of amplification is obtained by varying the dis- 

 tance between the objective employed and the sensitive plate, and an 

 amplification suitable to the object can be selected. Second, the ability 

 to see your image and arrange it according to the part you desire to 

 photograph ; this can be done on the ordinary ground focusing glass 

 of the camera, but when the image is thrown on a white ground, as it 

 is in this apparatus, it is more easy to select any particular portion and 

 to focus it roughly. This method is only suitable for photographing 

 transparent objects. It is more immediately designed for the delinea- 

 tion of histological subjects. 



Imagine an oblong lidless box laid on its side and securely screwed 

 to one end of a base-board two inches in thickness and two and a half 

 feet in length. The upper central part of this base-board, about one 

 inch in thickness, js made to slide in a dovetailed groove; the end of 

 this sliding part carries the holders for the plates employed, this holder 

 being an ordinary printing frame, from which photographic negatives 

 are printed. The size of the holder may be varied according to the 

 amplification required, and this sliding holder can diminish or greatly 

 extend the magnification as may be desired. The upper side of this 

 box has an oblong opening cut in it, over which a tin chimney is fixed, 

 thus allowing the lamp to approach or recede from the object stage as 

 may be desirable. Another opening is made in that side of the box 

 which faces the plate-holder and central with it ; this opening is closed 

 by a movable brass plate, having an adapter with the standard micro- 

 scopical screw soldered into it. This permits any objective with the 

 Society screw-gauge being employed. Below this plate a support 

 carrying the movable stage is fixed to the side of the box, this stage 

 being moved backwards and forwards by a long micrometer screw. 

 The object to be photographed is made to approach or recede from 

 the objective till a sharp image is thrown on the screen. The best 

 focusing screen is made by covering an old glass plate of any of the 

 standard sizes intended to be employed with a sheet of the smoothest 

 white paper by means of gum. This enables the operator to arrange 

 the object according to his judgment, and permits of a certain amount 

 of rough focusing. The finest focusing must be arrived at by other 

 means. Another plate of plain glass put into the holder and having 

 line lines drawn a short interval apart with a writing diamond (on its 

 surface which faces the objective) is looked at from the back through 

 an ordinary eye-piece or with a photographic focusing glass. When 

 the details of the object are seen sharply at the sanie time as the fine 

 lines, a sharply defined image will be thrown on the sensitive gelatine 

 plate, which it is intended shall occupy in the holder the place now 

 occupied by the plain glass. 



The light is derived from a microscopical lamp burning the purest 

 paraffine oil, in which is dissolved a lump of camphor of the size of 

 a walnut to the ordinary reservoir full ; this whitens the flame and ren- 

 ders it more actinic. A plano-convex lens with the convex side toward 



