The daily morning journal and courier., 1907-01-24
THE MAKING OF GLUE.
MATERIALS WHICH PRODUCT
 THIS USEFUL SUBSTANCE.

"dste from Hides, Horns and HOOtS 0i
 Animals is Used, but the sinews Ot
 Animals Slaughtered for Food Civ,
 the Best Results.
 Few substances are more generally useful than glue. At one time or an. other nearly every householder has tc use it, yet few persons know anything about the different kinds of which is best for the purpose in hand.
 For ordinary repairs to articles o1 wood, especially if no severe strain is to be placed upon the object, the pre- pared glues are convenient and ade- quate. They are therefore often choser in preference to the old fashioned sort But for strength and durability nc glue which is applied cold can com pare with the kind that Is first melted in a glue pot and then applied hot and of this kind there are many grades, which vary greatly in quality
 The manufacture of hard glue, as il is usually called-that is, glue which Is to be used hot-is to large degret the utilization of waste products. The raw materials are pieces and scrapings from hides, chips and dust from horn working factories, parings from hoofs and, best of all, sinews from animals killed for food in the great slaughter houses.
 The first process is a soaking ir lime-water, made thick enough to be called milk of lime' In this bath the sinews and other glue material remain for two weeks or more in or der that all the grease and blood may be eaten away, but immediately on removal the material is exposed tc currents of air, which allow any ad- herring lime to absorb carbonic acid This checks the action of the alkail on the animal matter and makes il possible to keep the material in the dry state for an indefinite period or until it is desired to use it.
 Previous to boiling, the scrap is again immersed for twenty-four hours in a bath of milk of lime. It is then placed in a caldron built on the plan of the housewife's familiar double boil CT. This kind of vessel is necessary tc prevent burning on" Water is add ed, and the mass is gently boiled unti a firm gelatinous liquid results from cooling.
 The clear portion is now drawn of from the first caldron into a second vessel and is known as first run sin. CIV glue''-the best of all. A smal quantity of alum dissolved in water is added for the purpose of clarifying the glue by causing it to precipitatt it's impurities.
 In a second double boiler the liquit remains several hours, till it is per. fectly clear. and is then run off into the congealing boxes, over the bot toms of which it spreads out in thir I sheets The boxes are run into the cooling rooms, where where they re. main until the glue has hardened enough to be removed in sheets but not enough to be brittle. In this state it is ready to be cut.
 The sheets are laid upon boards which have previously been wet tc prevent the glue from sticking. Here the cutting is done with tightly stretched brass wires as firlSin ot butter is cut by the country grocer.
 After a further drying on revolving nettings the sheets are dipped in hot water and rubbed with a brush tc give them a polish. They then pas: to the kilns for the stove drying. This removes all moisture and leaves what appears to be sheet of tran sucent yellowish brown bottle glass Indeed, the best sinew glue seems or casual examination to be nearly as hard as glass, and a quick sharr blow will produce a fracture that is clean cut and virtreous. The best ot this glue is light in color.
 The residuum left in the caldror when the first run of glue was drawn off is boiled and boiled again so long as any gelatinous matter can be ex- tracted from it. The product is glue of inferior grades, of course, but use full as seizing and for other purposes in various arts and industries. Al l though still claSSed as SlneW glue, tue later runs have not the strength of the first run. They are darker and less translucent.
 Not many wares ago nearly all the best glue was sold in sheets. Today by far the greater part is ground at the factories to the flneness of ordi- nary sawdust Since in this form il dissolves more quickly, 1t is so pre- ferred by woodworking factories, which use large quantities, but as the chan ces of adulteration are greater when the glue is ground the purchaser who wishes to be sure of strength and dur ability will choose the sheets.-E Edward Williston Frentz in Youths Compan- ion.
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