GLASS 



2507 



GLASS 



by Bishop Turnbull. It was endowed by Mary 

 Queen of Scots and her son, James I of Eng- 

 land. In 1864 new buildings were erected at 

 a cost of $2,350,000, and further additions have 

 been made at various times. The university 

 is now a corporation consisting of a rector, 

 chancellor, dean of faculties, principal 

 and professors. It maintains de- 

 partments and confers degrees in 



"GLASS 



arts, science, medicine, surgery, divinity and 

 law. Women are admitted, and in 1893 Queen 

 Margaret College, incorporated into the uni- 

 versity, was devoted to their sole use. The 

 students numbered about 2,800 before the War 

 of the Nations, in 1914, and of these 700 were 

 women. F.ST.A. 



Consult Howe's A British City: 

 The Beginnings of Democracy. 



LASS, one of those familiar sub- 

 stances that are put to so many uses we take 

 them quite as a matter of course. Yet, com- 

 mon as it is, glass adds more to our daily 

 comfort and happiness than the costliest gems 

 that the mines can yield. Our homes would 

 be dreary places indeed had we no window- 

 panes to give us light and through which to 

 view the world about us, and no one would care 

 to go back to the times when people drank out 

 of gourds and horns instead of glass goblets, 

 and used bottles made of skins. 



Glass has become indispensable in the home, 

 in the arts and in the commercial world. It is 

 as much a source of comfort to know that our 

 books are kept protected from dust behind the 

 glass doors of our bookcases, as to be able to 

 see the familiar titles and backs through the 

 transparent casing. The scientist can add his 

 testimony concerning the value of a substance 

 which forms the lenses of the microscope and 

 the telescope, and which is used in countless 

 other devices and instruments. The merchant 

 in the great city, who must utilize every avail- 

 able inch of space, transforms the basement 

 floor of his huge establishment into a minia- 

 ture department store, and solves the problem 

 of light by having the sidewalks adjoining the 

 building constructed of iron frames containing 

 many glass prisms. In the lovely stained glass 

 windows of the great cathedral and in beauti- 

 ful vases and costly tableware we see some- 

 thing of the artistic possibilities of this very 

 useful substance. 



What Glass Is. Glass is not a natural sub- 

 stance, like gold, silver or coal, but is an arti- 



ficial compound made by melting together 

 certain ingredients at a very high temperature 

 (from 1832 to 2732 F.). The principal ma- 

 terials used are: (1) sand (or crushed quartz 

 or flint), (2) lime, and (3) sodium carbonate, 

 or potassium carbonate or sodium sulphate. 

 For various forms of glass other materials are 

 added in varying proportions, such as man- 

 ganese, cobalt, copper, zinc, tin, arsenic, salt- 

 peter, etc.; pigments for coloring are also 

 added. Cheap grades of glass are made from 

 common sea and river sand, but for the manu- 

 facture of better qualities the sand is quarried. 

 Lime is found in nearly all varieties, but lead 

 oxide is substituted in making those which 

 require a brilliant luster and a high degree of 

 transparency, such as flint glass used for lamp 

 chimneys, for cut glassware and for some of 

 the lenses of optical instruments, and the 

 strass, or paste, used in imitation diamonds. 

 The lime has the effect of softening the glass, 

 and the injudicious use of this material has 

 caused many a beautiful piece of tableware 

 to become tarnished and even ruined after a 

 year of service. Potash-lime glass is much 

 harder and less easily melted than soda-lime 

 glass. 



Processes of Manufacture. In preparing the 

 materials which go into the making of the 

 better grades of glass the manufacturer puts 

 forth every possible effort to free the sand 

 from impurities. In many cases it is stirred in 

 great quantities of water, then burned in the 

 flames of a fire, and, finally, sifted through 

 copper gauze. Of the impurities which enter 

 it, iron is the most troublesome; if there is 



