84 



THE AMERICAN MONTHLY 



[May, 



it in the fixing bath, which consists of 

 a sokition of four ounces of hyposul- 

 phite of soda dissolved in a pint of 

 water ; this extracts all the silver 

 which has not been acted upon by the 

 light. The plate must now have a 

 great deal of washing to rid it of the 

 hyposulphite of soda ; this is thoroughly 

 done by placing it in running water 

 under a tap for half-an-hour. If the 

 film contains a trace of hyposulphite 

 it causes the image to fade out after 

 a time. 



Some plates have a tendency to frill, 

 that is, the edges of the film gelatin, 

 while wet, have a tendency to separate 

 from the glass and to curl up. To 

 prevent this the plate may be soaked 

 for about five minutes in a saturated 

 solution of alum, and then again well 

 washed and stood up on a sheet of 

 blotting paper to dry spontaneously. 



Now I have thought it well, before 

 commencing the demonstration, to gi\'e 

 you these details, that you may, bear- 

 ing them in mind, follow the practical 

 part with a clearer understanding of 

 what I am doing and why I do it, and 

 at the same time the box and its brass 

 contents have been getting warm — a 

 not unimportant item in the proceed- 

 ings ; forifj^ou begin your operations 

 before this takes place your glasses 

 will become dewed with the moisture 

 condensed on them, your brass will 

 be in a process of expansion from 

 this heat, your image will accordingly 

 be wanting in definition, and your 

 plate assuredly spoiled. I will now 

 proceed to photograph the blow-fiy's 

 tonjjue. T. C. White. 



Instructions in Dry-Plate 

 Photography. 



BY THE EDITOR. 



The object of these articles is to 

 enable the reader to make good pho- 

 tographs with the microscope, and to 

 prepare lantern-transparencies for use 

 in illustrating articles read before so- 

 cieties, or public lectures. 



In the preceding volume of this 

 Journal several articles were pub- 

 lished on the subject of photographing 

 from the microscope with dry plates. 

 It is not proposed to repeat much of 

 what was then published on this sub- 

 ject, but rather to supplement those 

 articles by some further instructions 

 and suggestions which later exuerience 

 has shown to be of value. The me- 

 chanical arrangements for photo- 

 graphing with the microscope have 

 already been described.* The inge- 

 nious apparatus illustrated in the figure, 

 although somewhat more expensive 

 than the apparatus previously de- 

 scribed, leaves nothing to be desired 

 as regards convenience and ready use. 

 The lantern is a most excellent one, 

 suitable for all purposes of the photog- 

 rapher. It has on one side a plate of 

 ruby glass to afford a non-actinic light 

 for developing dry plates. On another 

 side there is a plate of porcelain to 

 afford an even white light for copying. 

 There is no better lantern to be found, 

 but its cost will lead many to select a 

 much cheaper one to use in the dark 

 room for developing, and use a stu- 

 dent-lamp as the source of light for 

 taking the picture. 



In this article it is proposed to give 

 full instructions for developing and 

 finishing negatives, glass positives and 

 paper prints. The formulae for pre- 

 paring solutions can be relied upon 

 absolutely. Not one but we have per- 

 sonally used with satisfaction will be 

 given — in fact they are all the iden- 

 tical formulae we have used in our own 

 work. It may be laid down as an in- 

 disputable fact, that by following the 

 instructions intelligently, any person 

 can succeed in making excellent pho- 

 tographs with dry plates. 



As regards the brand of plate used, 

 we have found Carbutt's plates uni- 

 form and satisfactory. But it makes 

 very little dift'erence what plates are 

 used. Not that the products of dif- 

 ferent makers are alike, for they are 

 not ; but all are good, all will yield 



* Vol. iii. pp. 71 and 88. 



