94 ANNUAL OF SCIENTIFIC DISCOVERY. 



purposes, the method is worth knowing. London Photographic 

 Neujs. 



A New Way of Cutting Glass. It frequently happens that 

 chemists and others wish to utilize some bottle or piece of broken 

 glass apparatus, by cutting it in a certain manner. As some per- 

 sons experience great difficulties in doing this, we give for the 

 benefit of such a very simple means by which glass can be easily 

 cut in any direction. 



Take of powdered gum tragacanth, one-eighth of an ounce, dis- 

 solve it in sufficient water to form a middling thick paste, then dis- 

 solve one-fourth of an ounce of finely powdered gum benzoin in the 

 least possible quantity of strong alcohol ; mix both solutions thor- 

 oughly, add to this a sufficient quantity of finely powdered beech- 

 wood charcoal to form a doughy mass a little thinner than pill com- 

 positions. Out of the above mass roll little sticks about 4 inches 

 long and 3 lines thick, and let them dry spontaneously. If, after 

 being thoroughly dried, one of these sticks is ignited, it burns to a 

 fine point until it is entirely consumed. 



The glass to be cut is first scratched deeply with a diamond or 

 file, then one of the above sticks is ignited and held with a very 

 slight pressure on the crack, in the direction the cut is to proceed, 

 and it will be found that the cut will follow in any direction the 

 "taper" may be drawn. The taper must be withdrawn every 

 few seconds and brought to a more lively burn by brisk blowing, 

 as it is cooled by the contact of the glass. 



By these means all kinds of vessels can be formed from other- 

 wise useless bottles. Thus, for instance, by cutting the tops off 

 of bottles, jars are obtained which are excellent as precipitating 

 vessels. Humphrey's Journal. 



Drilling Glass. To the old mode of boring glass with a file 

 wet with oil of turpentine, a correspondent of the " Chemical News " 

 adds an amendment from a German source, confirmed by his 

 experience, to the effect that dilute sulphuric acid is much more 

 effective, with less wear of the tool, than oil of turpentine. It is 

 stated that at Berlin, glass castings for pump barrels, etc., are 

 drilled, planed, and bored like iron ones, and in the same lathes 

 and machines, by the aid of sulphuric acid. 



Glass Printing". De Mothay has prepared an ink for printing 

 on glass by means of rollers similar to those used in calico print- 

 ing, after which the glass is subjected to heat and the picture is 

 vitrified and fixed in the glass, without producing any distortion 

 or imperfection. Many^thousands of plain patterns and mosaics 

 of stained glass, produced by this process at a very cheap rate, 

 are already in use for the decoration of church and other windows. 

 The colors are mixed with a solvent of a silicate or silico-borate 

 of potash and lead, as usual in painting on glass, and this compo- 

 sition, rendered plastic by resin in turpentine, is applied thickly 

 to the rollers and transferred into glass, after which it is vitrified 

 in the usual manner. 



