514 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [48] 



to all other methods of carrying ofl the Nvater, not only because it is 

 self-acting in keeping the water at a level even at times when the 

 supply of water is superabundant, thus rendering outside ditches un- 

 necessary, and because the draining of the pond can thereby he easdy 

 managed and regulated, but also because the change in the height of 

 the water, when the supply is scanty, can readily be recognized by it. 

 When the water l\illsone can, so to speak, read its height on the stand- 

 pipe, for which purpose it will be well to make the little boards all of one 

 and the same height and number them; and as it is important for the 

 pond culturistto be able to find the diflerent causes of the varying pro- 

 ductiveness of his ponds, ho will be aided in this by the stand-pipe which 

 will enable him to ascertain at once the height of the water. Stand- 

 pipes will, therefore, be of special importance in sky ponds. 



D.— Thk tap-exit. 



This consists simply in placing a suitable^ piece of wood, called the tap, 

 iu the opening where the stand-pipe, described in the ])receding chapter, 

 joins the exit-pipe. In small ponds short, and in large ponds long, taps 

 are used. Tscheiner says regarding short taps : " The short tai>, which 

 does not protrude above the surface of- tho water, will prevent thiev- 

 ing, and deserves special mention. It is about (JO to 70 centimeters 

 long and shaped exactly like the lower portion of a common tap. After 

 it has been tirmly inserted in the hole, some centimeters, both iu depth 

 and breadth, of the wood are removed from the top, which is covered 

 with a broad piece of iron having a long and narrow hole in the center. 

 For drawing the tap a so-called key is necessary, consisting of a cross- 

 shaped i)iece of iron, which must tit in the hole. To the other end of 

 the key a pole is fastened. If several small ponds are to be closed by 

 a short tap, the holes in the taps should be all of the same size, so that 

 they can all be opened with one key. To open a pond closed in this 

 manner, seek the hole with your key; as soon as found, insert the key; 

 turn it half around, and thus lift the tap from the water. This can, of 

 course, only be done in small ponds, when the taps are not large, and 

 consequently not very heavy. In very small ponds, where diminutive 

 taps are used, it will be sufficient to make at the top of the tap a small 

 notch, ill which, when it is to be drawn, the so-called pond-hook is in- 

 serted." 



It should be observed that these contrivances for drawing a short tap 

 will not suffice for drawing it out entirely, as it has to be driven in very 

 firmly iu order to keep the arrangement water-tight. It will therefore 

 be necessary in all cases to loosen the tap by knocking it several times, 

 when it can be taken out without the aid of auy special contrivance. If 

 the method described above is to be employed, it should not be forgotten 

 to give the iron on the toj) a coat of paint to keep it from rusting. At 



the moment when the tap is drawn, a piece of wire-work is inserted in 



