CHAPTEK II. 

 PREPARATIONS FOR WORK. 



A GREAT deal of time> trouble and expense will be saved by 

 a careful consideration of certain matters before any attempt is 

 made at actual work. It is probable that after actual work 

 has been carried on for some time alterations may be found 

 necessary and improvements may suggest themselves ; but the 

 earlier lessons of practice and experience will be well nigh 

 wasted if there is not in the first arrangements a certain amount 

 of forethought and fore-knowledge. We shall here, therefore, 

 endeavor to smoothe the way for the beginner by giving hints, 

 as close as possible to directions, on such matters as apartments, 

 and apparatus of a general nature, leaving a more detailed de- 

 scription of special apparatus for future chapters. 



A great advantage will arise from having two apartments 

 communicating with each other for the two branches of the 

 work : the microscopic or exposure work, and the photographic 

 or development work. If two communicating apartments are 

 not available, two adjacent ones may do almost as well; or 

 with certain evident precautions one chamber may be used for 

 both lines of operation. Wherever the apartment for making 

 the exposure may be, it is of the utmost importance that it be 

 steady ; with a good sound floor, and as far as possible removed 

 from house or street traffic. No place is usually so suitable as 

 a basement or half-basement cellar, and if this ground apart- 

 ment have floor and walls of cement, and a strong ceiling, it 

 will probably be perfectly adapted for the work. But even 

 such an apartment should be as far as possible distant from 

 street traffic, if the finest photo-micrographic work is intended. 

 Mr. E. M. Nelson, alluded to in last chapter, works in a cellar 

 such as just described, using for his apparatus a base not only 

 itself very heavy but further weighted with several hundred- 



