68 PHOTOGRAPHY FOR NATURALISTS. 



on to the tank from below. The result was in some 

 degree successful, the under surface of each fish 

 appearing a brilliant silver, and the general effect 

 being almost dazzling. By the use, moreover, of side 

 reflectors, harshness of contrast was, to a certain 

 extent, avoided. There were, however, serious draw- 

 backs to this concentrated form of illumination. 

 Every small scratch or defect upon the glass surface 

 was shown up with irritating exactness, and each 

 fish cast one or more shadows on the glass behind 

 it. The experience thus gained determined the 

 writer to avoid, if possible, artificial lighting, whether 

 by means of reflectors or flashlight, and to construct a 

 fresh tank, whose sides should be of the thinnest and 

 whitest plate glass obtainable. A consideration of his 

 own case, and of that of the photographer-naturalist in 

 general, led him to the following conclusions. The 

 tank, whose object is to confine living fish within 

 such a space as will enable a photographer to keep 

 them to some extent in focus while swimming, must 

 fulfil these requirements : Its sides must be of the 

 thinnest and whitest plate glass, sufficiently strong to 

 withstand the head of water contained between 

 them. It must be portable. It must be of cheap 

 material, and easily constructed. There must be pro- 

 vision for widening or narrowing to suit, within certain 

 limits, fish of various sizes. 



The following is a description of the tank which 

 was eventually constructed. Only such material as 

 happened to be at hand was utilised, with the exception 



