252 Fortieth Annual Meeting 



mens in place to the aquarium. The glass is held vertically 

 by slipping its edges into grooves at the sides and bottom 

 arranged to receive it. The operator may expand the fins 

 if desired and hold them in place vv^ith insect pins which may 

 easily be concealed from the eye of the camera. It will be 

 found that the buoyancy of the water will hold the specimen 

 out from the glass screen in a natural position. The water, 

 too, will take up any body juices that would run out to stain 

 the background or to otherwise annoy the operator at the 

 critical moment. 



Care must be taken to have the glass sides of the acjuarium 

 both dry and clean, for a drop of water or a finger mark 

 may ruin an otherwise perfect negative. By examining the 

 illustration, it will be seen that the light is admitted into the 

 studio through windows at the right and left of the camera, 

 the dotted lines indicating the direction taken by the light 

 reflected from the glass front of the aquarium. The light 

 which falls upon the object to be photographed is sent back 

 into the camera, while the shadows which the object casts 

 are diffused by the light which passes behind it and strikes 

 on the background. 



The background should never be of a dark color. Black 

 makes the glass aquarium front reflect light like a mirror. 

 White, light grey, or even brown, may be used to advantage, 

 and the greater the distance between the object and the 

 background the better. When using glass aquaria or mount- 

 ing screens, it is advisable for the operator to wear dark 

 clothes, otherwise after satisfying himself that the image on 

 the ground glass is free from reflections, the light from a 

 white apron at the moment of exposing the plate may result 

 in the securing of undesired reflections, that show plainly 

 when the plate is developed. 



A large number of satisfactory negatives of a great 

 variety of marine forms were taken by this method. Some 

 of them, as certain shells, were photographed in the air and 

 again in water. The experiment proved conclusively in 

 each case that certain obscure markings that did not show 



