398 



THE GUIDE TO NATURE. 



at the ends where it is well to use 

 ten penny. For five quarters' stuff ten 

 penny nails are used, excepting at the 

 ends which require twelve penny. 



When large tanks are made of heavy 

 lumber spikes are required and gener- 

 ally rods bolted across the ends are 

 necessary. In such tanks, too, the bot- 

 tom planks are often run lengthwise 

 and held in place by bolt rods running 

 across and through them ; but the tanV 

 should not be too long or else it will 

 sway in the middle. 



All lumber is not only more easily 

 worked when planed but fits better and 

 is more readily kept clean when in us< 

 It can be purchased surfaced and ai*l 

 cut ends quickly succumb to an iron 

 smoothing plane. 



Try all work before cementing by 

 lightly tacking together. 



Cements, properly speaking, with 

 wooden tanks are caulking materials 

 and not cements, for they do not unite 

 surfaces but fill up the spaces between 

 them. For instance one method of 

 making a tank tight is, before nailing, 

 to bruise with a dull cold chisel a rough 

 groove and in this groove lay a few 

 strands of lamp wicking. When the 

 tank is nailed together and water ad- 

 mitted the bruised wood swells into 

 place again and makes a packing of 

 the lanq) wick. However, in this case 

 the additional application of some white 

 lead would probably make assurance 

 doubly sure. 



Stiff asphaltum varnish is a good 

 cementing material. Common pitch an- 

 swers if it can be kept soft while put- 

 ting the tank together. White lead-, 

 red lead and zinc white can all be used 

 in close seams. For the bottom boards 

 a mixture of zinc, white, one part, and 

 common putty, three parts, gives the 

 best result. To repair corner leaks, 

 when they occur, dry the box and pour 

 melted pitch in the angles and work 

 it in well with a hot iron. Generally 

 the less cement used beyond what is 

 necessary to level inequalities the bet- 

 ter will be the union. 



For an improvised tank an old wooden 

 watering trough makes the best of all 

 tanks. Casks in which olives are im- 

 ported, cut in half and rehooped, fur- 

 nish good tanks of about eight gal- 



lons' capacity. The ordinary cedar 

 washing tub does very well after proper 

 soaking and seasoning. Wood fibre 

 tubs are also very good. Petroleum 

 barrels cut in half and burned out make 

 fair small tanks, particularly when 

 partly buried in the ground. 



Barrels, however, that have contained 

 whisky or other spirits, fatty matters, 

 dyestuffs or anything injurious to life, 

 must not be used unless one is certain 

 that long seasoning has rendered them 

 safe. It is better to avoid them alto- 

 gether. It is well to remember, too, 

 that until well seasoned all oak casks 

 give off some tannin. 



The soapstone washtubs are divided 

 into compartments holding about 

 twenty-five gallons and make fine 

 tanks. The soapstone sinks are good 

 also for shallow hatching boxes A soap 

 stone, porcelain or porcelain lined bath 

 tub furnishes an excellent tank of very 

 considerable capacity. For hatching 

 and many operative purposes quite 

 large agate ware basins are procurable 

 and especially suitable. 



If true ponds are desired instead of 

 tanks we must consider that a pond is 

 practically a tank of some water-tight 

 material either placed or constructed 

 below the level of the earth. Therefore 

 a wooden box of any size, merely nailed 

 together with the sides and bottom 

 battened and all the joints pitched, can 

 be put in the ground and termed a 

 pond. The wood of such box need not 

 be heavy as the surrounding soil takes 

 up all the pressure. With such a gen- 

 eral idea as a starting point such a 

 crude method can be improved upon 

 in various ways : 



First. The sides can be sloped. 



Second. The wood bottom can be 

 left off and replaced with grouting and 

 a cement finish. 



Third. Xo wood need be used at all 

 and all the dimensions be made of 

 grouting and cement. 



Fourth. The bottom remaining of 

 grouting and cement, the sides can 

 be built of either stone or brick. 



In pond work there are several 

 points to remember: 



First. Lime mortar is not suitable 

 as it will not harden. It is true that 

 for brickwork in a greenhouse it can 



