294 



Popular Science Monthly 



be substituted for the lamp oil, if a bulb 

 IS placed in the jar. 



The other methods of heating the 

 aquarium differ from those just described 

 in that a lamp is placed beneath the tank, 

 which must stand upon a platform or frame- 

 work of artistically designed ironwork. 

 But only those aquariums may be so 

 heated which are either built entirely 

 of glass or those which have zinc bottoms. 

 Both are placed in pairs with their refuse 

 corners facing each other. Those made 

 entirely of glass receive an extra piece of 

 copper placed about an eighth of an inch 

 from the glass bottom which the flame 

 must strike. Aquariums with sheet metal 

 bottoms do not need this extra piece of 

 copper, when this method of heating 

 is used. 



Two other ways in which the aquarium 

 may be heated, remain to be explained. 

 Both work on the principle of water cir- 

 culation. This method produces the best 

 results, for none of the heat is wasted. 

 One of the tanks receives a small box-like 

 insertion, made of sheet zinc, which 

 should cover the bottom of the tank. 

 Two tubes, one shorter than the other, 

 are soldered to the top of the box. The 

 tank may then be arranged like an or- 

 dinary aquarium so that only these tubes, 

 covered with fine wire netting, project 

 out of the sand. The water, in the box 

 immediately below the soil of the aqua- 

 rium, is heated with a small lamp. The 

 water, as soon as it becomes warm, rises 

 through the long tube, while the shorter 

 one lets the cold water sink into the box. 

 In this way, a continuous circulation is 

 kept up. Another advantage of the 

 box is that it does not heat the soil of 

 the aquarium, which would materially 

 injure the plants. 



The other and last method is similar 

 to the preceding one. Instead of the box, 

 a U-shaped piece of tubing is soldered 

 to the bottom of the aquarium. The 

 curve, which projects about an inch 

 below the aquarium, is heated. All 

 beatable aquariums should be covered 

 with a piece of glass when heated, unless a 

 glass jar is used. Then the i)rotecting 

 glass cover should have a large opening, 

 corresponding to that of the jar, and it 

 should be so situated that the heated 

 air may escape and a fresh cool supply 

 reach the flame. — Dr. E. Bade. 



.y^y 



A Secure Fastening for an 

 A-Shaped Sign 



1UNCH room and other sidewalk signs 

 -/ in the shape of the letter A will not 

 stay in place on a windy day. Devices 

 which might hold them steady are usually 

 inconvenient to pedestrians. But with the 

 fastening shown in 

 the illustration, 

 the holding device 

 at the base of the 

 sign may be set 

 below the surface 

 of the walk, where 

 it will be in no 

 one's way. When 

 the turnbuckle is 

 tightened, the sign 

 cannot be blown 

 away. The eye 



may be on a stake driven into the earth 

 where sidewalks are placed on the ground, 

 or where a sign is used outside of the 

 walk; but in the case of a cement walk, the 

 eye may be set in the gravel or grout 

 when the walk is laid. The holding de- 

 vice may consist of a chain or of a rod with 

 an ordinary turnbuckle in its center. The 

 chain or rod is attached under and at the 

 top of the boards and has a hook at the 

 lower end for making connection with the 

 eye in the walk. — G. P. Lehmann. 



Bolt with turnbuckle 

 fastened in sidewalk 



Using Shingles to Make a Thatch- 

 Like Effect at Eaves 



PROBABLY every artistic soul has 

 longed for a little home with droopy 

 roof lines that stoop to meet the climbing 

 ivy on the walls. 

 You can go a long 

 way toward get- 

 ting it by making 

 a bouquet of your 

 shingles. Bore a 

 hole through the 

 first bunched 

 line of shingles ex- 

 tending over the 

 eave, and wire 

 them in place. Of 



course it is necessary to slope the rafter 

 ends and to put on the first sheathing 

 board at a slope which will take the 

 bunched shingles.— W. B. Smith. 



Shingles bunched 

 to make the 

 thatch effect 



