30 



THE 



AQUARIUM 



# 



exact action of the bubbles, and I can 

 say that it works to absolute perfection. 

 By the movement of particles of dirt 

 within the pipes one can see the speed 

 and movements of the water, and after 

 long watching, I never saw a particle of 

 the waters interchange. To have the 

 water from the heated system enter the 

 aquarium would be undesirable, as this 

 water has had practically all the oxy- 

 gen driven out of it by the action of the 

 heat. Furthermore, if the ac^uarium 

 water were allowed to freely enter the 

 system, there would no doubt, from time 

 to time, be particles go into the pipe which 

 would clog it up. The hook is made sep- 

 arate from the rest of the piping and is 

 attached by a rubber hose of the same 

 size. This makes the hook detachable so 

 that the system can be readily filled. 



Experiments on direct heating have 

 been conducted in four ways. The first 

 is by use of an inverted pan in the centre 

 of the aquarium, a hole having been cut 

 in the bottom of the aquarium the size 

 of the pan, in order to allow the heat to 

 be applied to the inside of the pan. 

 There are several ways of cutting a hole 

 and securing the pan. Probably the 

 simplist is to make a new base for the 

 acjuarium out of an equal mixture of 

 sand and cement, setting the pan in at 

 the desired height. I use a small enamel 

 milk pan about four inches across and 

 one and one-half inches deep. If an 

 aquarium has a thin slate bottom a 

 series of holes may be drilled in the 

 form of a circle. This method of heating 

 has the advantages of being extremely 

 efficient, requiring no attention and hav- 

 ing the heating surface well above the 

 sand. This allows free circulation of 

 water over the heating surface and pre- 

 vents the roots of the plants from inter- 

 fering with the heatinir. 



Another direct method (see Fig. II) 

 through the bottom of the aquarium 

 consists in cutting a hole of about one 

 inch in diameter in the bottom and 

 pouring either tin or lead into the hole. 

 The lead should be allowed to spread a 

 little at the top so as to make larger 

 contact with the water. The fiame may 

 be applied directly to the underside of 

 the block of metal. It is advisable to 

 put a few pebbles over the upper side 

 so as to avoid the risk of having the fish 

 come in direct contact with the warm 

 metal. I would personally have sup- 

 posed this method to be undesirable as 

 even with the pebbles over the heated 

 spot there must be quite a great deal 

 of local heat in a small place through 

 which the fish swim. This would seem 

 to be undesirable, but I have seen a 

 large aquarium, containing many kinds 

 of fish, apparently enjoying the best of 

 health, which was heated in this man- 

 ner. The illustration shows the metal 

 in slightly enlarged proportions in order 

 to make it clear. 



If one has an aquarium with a metal 

 bottom, there is no reason why the heat 

 should not be applied directly to it. A 

 few pebbles over the hottest part would 

 be desirable and if one wished to pre- 

 vent the roots of the plants from en- 

 croaching over this spot, it could be 

 done by the use of a zinc ring about the 

 width of the depth of the sand (one to 

 two inches) and perhaps four inches in 

 diameter. 



Many aquaria have been built with a 

 drain pipe of about one inch diameter. 

 This can be utilized very nicely for di- 

 rect heating (see Fig. III). In this ex- 

 periment I have used what is called 

 "Rope Brass Pipe." It is slightly cor- 

 rugated and therefore adds a little ef- 

 ficiency. Any brass pipe, however, to 



