82 



ttquatlc JUC* 



ing with this point of view in mind, a 

 scheme for feeding continuously was de- 

 veloped, and as most species confined in 

 aquaria have been observed to rest at 

 night, feeding during the daylight hours 

 need only be considered. It might be 

 said to be the general practice in com- 

 mercial hatcheries devoted to the rearing 

 of the Salmonoids, etc., to detail attend- 

 ants to the feeding of the fry by hand at 

 definite intervals. This in moderately 

 large establishments amounts to a con- 

 tinuous process, it being time to feed the 

 first trough full of young by the time the 

 last has been finished. Automatic de- 

 vices have been experimented with to 

 eliminate this expenditure of energy, 

 usually depending on water power, but 

 so far as the writer's information goes 

 have been unsatisfactory. Of course a 

 point enters here that does not concern 

 the aquarist as the food usually used by 

 these establishments is wet and mushy, 

 not being dessicated as is the customary 

 aquaria fish food. 



The accompanying sketch and photo- 

 graphs explain in general the arrange- 

 ment of the device. The clock which 

 controls the mechanism is seen to be 

 simply a switch of which the minute 

 hand forms the lever with a small piece 

 of phosopher-bronze wire at its tip, mak- 

 ing contact with the stationary points at 

 VI and XII. The closing of the circuit 

 at these periods causes a certain quantity 

 of food to be dropped into the aquarium 

 below. This period can be lengthened or 

 shortened at will by decreasing or in- 

 creasing the number of contact points. 



The food hopper is simply a small 

 metal container to which the working 

 elements of a common door bell have 

 been attached. The gong and clapper 

 have been removed, the rod for support- 

 ing the clapper being passed through the 

 hole in a strip of rather heavy copper 



that forms the valve, so allowing only a 

 certain predetermined amount of food to 

 escape at the proper time. The two dia- 

 grams "A" and "B" show this action. 

 While at rest "A" a hole in the bottom of 

 the reservoir is directly above the large 

 opening in the moving valve piece, which 

 allows the opening to fill with food. 

 When an electrical impulse is sent 

 through the magnets causing them to 

 attract the armature, it is evident that 

 the strip will assume position "B" and 

 block the hole in the reservoir and al- 

 low the food that was previously in the 

 valve strip opening to fall below, as it 

 passes beyond the strap-like piece that 

 formerly held it in place. Of course a 

 single stroke bell should be used, or the 

 vibrator shunted around if the bell is of 

 the vibrating type. The amount of food 

 ejected at a time is determined by the 

 size of the opening made in the moving 

 strip and the thickness of the metal em- 

 ployed. A number of interchangeable 

 strips might be employed for experimen- 

 tal work. 



A battery of three dry cells will suf- 

 fice to operate this device, although a 

 much more positive action can be obtain- 

 ed by using 4 or 6 in series, or any other 

 available source of suitable current may 

 be used. A switch introduced in the cir- 

 cuit (below the clock), was used to stop 

 the action in the evening and start it 

 again in the morning. This was not such 

 a hardship as one might imagine, as the 

 writer naturally made it a practice to 

 visit the aquaria before leaving home in 

 the morning and again in the evening be- 

 fore retiring. Thus the act of throwing 

 the switch in the proper direction at the 

 appropriate time soon became as habitual 

 as winding one's watch. However, a re- 

 finement could easily be introduced do- 

 ing away with this switch, by engaging 

 an idle gear (on the reverse side of the 



