SCIENCE- G OSSIP. 



193 



A GARDEN POND. 



By J. Leonard Monk. 



rjlHEKE are many points wrapt in doubt and 

 -*- mystery connected with the aquatic life of 

 our freshwater tarns and rivers. As instances, we 

 may cite such cases as the necessity of better 

 observation of those small worm-like animals, the 

 Gasterotricha, little understood as yet ; the dis- 

 covery of the males of some species of Rotifers ; 

 and better knowledge of the aquatic caterpillars 

 of certain moths, " china marks," etc. There is un- 

 doubtedly much more to be learnt of the develop- 

 ment and life history of aquatic insects by a careful 

 study of them in their natural surroundings. Even 

 to willing workers, however, in this field of research 

 it is often only on special occasions they are able 

 to pursue their investigations, especially if they 

 should find themselves time-hampered, unfortunate 

 town-workers, as is the case with the writer. 



To overcome these difficulties, however, I re- 



This arrangement, both for economy and result, 

 in my estimation, after having given both a fair 

 trial, far surpasses the ordinary glass aquarium. 

 The advantages claimed for it are the following : — 

 A maximum of surface is exposed to the atmo- 

 sphere, ensuring the freshness of the water and a 

 certain amount of natural food-supply for such 

 animals as frogs and newts, which feed on living 

 insects, worms, etc. ; also the natural succession 

 of life takes place month by month. A good supply 

 of aquatic weed should be established on a gravel 

 bottom, to prevent stagnation of waste organic 

 matter, as it is well to change the water as rarely 

 as possible, for the retention of microscopic life. 1 

 have not changed the water in my aquarium for the 

 last eighteen months, but it still remains perfectly 

 fresh. A small quantity has, however, been added 

 from time to time to supply loss by evaporation 



mm 



Construction of a Garden Pond. 



a. Sloping zinc border, b. Outlet cavity, c. Layer of fine cement, d. Layer of rough cement, e. Layer of bricks. 

 ¥. Inlet pipe. G. Outlet pipe. h. Stopper. 



solved to try an experiment which has worked 

 most satisfactorily, bearing good results. It is 

 therefore the object in this article to give a short 

 description of the method used, that others may 

 also share the pleasure and instruction afforded 

 by it. 



The plan consisted in making a small garden 

 pond, of which the illustration gives a sectional 

 view. I have found the dimensions 4 feet in dia- 

 meter by about 1 foot 6 inches in depth quite large 

 enough for the purpose. An outlet pipe leads into 

 a cavity loosely filled with rubble, to allow the 

 water to drain into the earth. On the other side a 

 feed pipe is fixed, which can be used with the aid 

 of an indiarubber tubing connection, if there is not 

 a convenient water-supply. The bordering zinc 

 should be well tarred and bent over the water at 

 about the angle indicated, which effectually pre- 

 vents the escape of animals with straying pro- 

 pensities. 



December 1901.— No. 91, Vol. VIII. 



The most suitable and hardy plants I have found 

 to be frogbit, Anaoharis, and Potamogeton. Other 

 species may, of course, be substituted according to 

 taste and demands. 



The stock of animal life to be introduced will 

 depend on the direction in which one's interests 

 are chiefly engaged. My special hobby has more 

 particularly been the Amphibia, which readily 

 make themselves at home ; so completely, in 

 fact, that I have had the satisfaction of seeing 

 many of them undertake family matters. Chief 

 among these important events was the pairing and 

 successful oviposition by some Bombinator pachypus 

 (fire-bellied toads), which for two years previously 

 had been kept in a glass aquarium without pair- 

 ing. A few of this brood are still living, having 

 successfully passed their critical juvenile stages. 



For the student wishing to follow the develop- 

 ment of the common frog, no better medium could 

 be devised. I was less fortunate with Pelobates 

 Published November 25th, 1901. 



