314 



Popular Science Monthly 



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Details of construction of window opening device 



Two binding-posts are fastened to the 

 back of the clock. One post is in elec- 

 trical contact with the frame of the clock 

 while the other is carefully insulated 

 from it. A fiat spring is attached to the 

 insulated binding-post and bent into such 

 a position that the alarm key will come 

 into contact with it as it rotates. It is 

 not necessary to wind the alarm up com- 

 pletely but only to give it a fraction of 

 a turn so that in unwinding it will touch 

 the flat spring in passing. 



The apparatus should be connected up 

 as shown in Fig. 2. One dry cell is suf- 

 ficient to operate this device. A press 

 button switch may be included in the cir- 

 cuit as shown in Fig. 2. This press- 

 button is for use when it is desired to 

 close the window at any time other than 

 that for which the alarm clock switch is 

 set. 



One alarm clock switch may be used 

 to close any number of windows at the 

 same time by simply connecting the 

 magnetic latches on the different win- 

 dows in series. It will, of course, be 



necessary to increase the number of cells 

 in the battery if more than one window 

 is to be operated. 



For Conserving Heat in Steam Pipes. 



AN excellent covering for steam pipes 

 may be made from materials that 

 are almost always available. Take some 

 fine sawdust and screen it through a 

 sieve to remove any foreign bodies. 

 Prepare a thin paste of flour and water, 

 and mix the sawdust thoroughly with 

 this paste. With a small trowel, the mix- 

 ture so prepared should be applied in 

 about 5 coats to the steam pipes while 

 they are slightly warm. Each coat should 

 be thoroughly dry before the next is ap- 

 plied. If the steam pipes are in an ex- 

 posed situation, 3 or 4 coats of coal-tar 

 should be applied after the paste has 

 dried ; if inside a building, this water- 

 proofing is unnecessary. Steam pipes 

 treated with the sawdust as above lose 

 very little heat and, in addition, the mix- 

 ture is much cheaper than patented prep- 

 arations. 



