/o Laboratory Arts 



American tool with a wheel cutter of glass-hard steel is fairly 

 efficient when new, and is much cheaper. Failing this again, 

 a freshly broken file will be found to cut glass reasonably well, 

 but much more care has to be exercised in making sure that 

 the glass has been cut, not scratched, before attempting to 

 break it. 



A diamond really cuts the glass right through, although it 

 touches but the surface, whereas in using either of the other 

 tools it seems necessary to remove some of the material, and 

 make a V in the surface, along which the glass naturally cracks 

 under strain. 



No difficulty will be experienced in cutting window glass 

 with a diamond one has to be careful to make a true cut 

 from the start; for even a diamond, wrongly used, will 

 tear the glass, much to its own detriment. The cut having 

 been made, the glass is broken by placing the thumbs on 

 the upper side of the glass, the fingers underneath, one hand 

 on each side the cut, and pulling rather than bending the 

 glass apart much the same action as though one were trying 

 to bend the glass at the far end of the cut. 



Patent plate should be first cut, as above, on a table of 

 green baize or similar soft material, then turned over and 

 tapped smartly along and above the cut, which has the effect 

 of bringing the cut through. After this it may generally be 

 broken apart with ease and certainty. 



Plate glass is treated similarly. As the glass is heavy, it is 

 a good plan to slip a rule under the glass touching the cut 

 (which in this case should be on the upper surface of the 

 glass), and press sharply down on the other piece about 

 the middle of the cut . 



Both plate and " patent plate " are expensive, and it is 

 well to practise upon some old pieces before attempting any- 

 thing important. Usually a special diamond is kept for 

 plate glass. 



Should it happen that glass must be cut with a file, choose 

 a fine rat-tail, or small triangular " saw " file, snip off the end 

 as close as possible so as not to injure the file, and try point 

 after point until one is found which really cuts. Then cut by 



