. Bacteria in relation to plant diseases. Bacteriology; Plant diseases. VENTILATION OF DARK-ROOM. 14'J c LOADING SHELF i\j 8 m. ,c 6m 2 ft 9 m ^ ^ ^ ^ 17 in u. -~j kl 3; <Ji c o K t t^ c --J ^ -\ nriDQ t Fig. in use much of the time, some Tlie writer accomplishes this by an electric fan placed in the mouth of an air-shaft which extends from the ceiling to 6 or 8 feet above the roof These shafts are c}'lindrical, i foot in diameter, made of heavy sheet- iron and surmounted by a broad, mushroom - shaped cap. The interior is painted a dead black, and as an additional precaution against
. Bacteria in relation to plant diseases. Bacteriology; Plant diseases. VENTILATION OF DARK-ROOM. 14'J c LOADING SHELF i\j 8 m. ,c 6m 2 ft 9 m ^ ^ ^ ^ 17 in u. -~j kl 3; <Ji c o K t t^ c --J ^ -\ nriDQ t Fig. in use much of the time, some Tlie writer accomplishes this by an electric fan placed in the mouth of an air-shaft which extends from the ceiling to 6 or 8 feet above the roof These shafts are c}'lindrical, i foot in diameter, made of heavy sheet- iron and surmounted by a broad, mushroom - shaped cap. The interior is painted a dead black, and as an additional precaution against the entrance of light it carries a sleeve of tlie form .shown in fig. 131. This effectu- ally cuts out light. The air is pumped out so rapidly by a de- vice of this sort that not the least inconvenience is experi- enced in working all day in a very small room. If only one or two persons The very convenient heavy camera shown in fig. 124 ma)- also be used for natural-size work, arranged as shown in fig. 129. In tliis connection the Starrett cross-level shown in fig. 130 will be found ver}' convenient for leveling the back of the camera. Very excellent cameras are made by the Centur}' Camera Company. Their Long-focus Centur}- Grand leaves little to be desired in the wa}' of a convenient, perfect-working in- strument. The dark-room for development is an important subject. The cliamber must be light-tight. At the .same time it ought to be roomy and well ventilated. If the room is small and means of removing the foul air becomes Fig. *FiG. 135.âDiagram of sniall dark-room shown in iiy. 134. Standing in the middle, a man can touch the walls in either direction. In the ceiling is a foot-wide pipe extending 6 feet beyond the roof and capped with a broad mnshroom top. In the lower end of this pipe is an electric fan, which pumps foul air out of the room. Light is prevented from entering by partial cross-septa projecting from opposite sides of the air-shaft, and also
Size: 1543px × 1619px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherwashingtondccarneg
