682 



GLUE 



The thrco successive boils furnish threo different qualities of glue. 

 Flanders or Dutch glue, long much esteemed on the Continent, was made in tho 

 manner above described, but at two boils, from animal offals well washed and soaked, 



1115 



.' o as to need less boiling. The liquor being drawn off thinner, was therefore less 

 coloured, and being made into thinner plates was very transparent. The above two 

 boils gave two qualities of glue. 



By the English practice, the whole of the animal matter is brought into solution at 

 once, and the liquor being drawn off, hot water is poured on the residuum, and made 

 to boil on it for some time, when the liquor thus obtained is merely used instead of 

 water upon a fresh quantity of glue-materials. The first drawn off liquor is kept hot 

 in a settling copper for five hours, and then the clear solution is drawn off into the 

 boxes. 



The boxes are made of deal, of a square form, but a little narrower at bottom than 

 at top. When very regular cakes of glue are wished for, cross grooves of the desired 

 square form are cut in the bottom of the box. The liquid glue is poured into tho 

 boxes placed very level, through funnels furnished with filter cloths, till it stands at 

 the brim of each. The apartment in which this is done ought to be as cool and dry 

 as possible, to favour the solidification of the glue, and should be floored with stone 

 flags kept very clean, so that if any glue run through the seams, it may bo recovered. 

 At the end of 12 or 18 hoxirs, or usually in the morning if the boxes have been filled 

 over-night, the glue is sufficiently firm for the nets, and they are at this time removed 

 to an upper story, mounted with ventilating windows to admit tho air from all quar- 

 ters. Here the boxes are inverted upon a moistened table, so that the gelatinous 

 cake thus turned out will not adhere to its surface ; usually the moist blade of a long 

 knife is insinuated round the sides of the boxes beforehand to loosen the glue. Tho 

 mass is first divided into horizontal layers by a brass wire stretched in a frame, like 

 that of a bow-saw, and guided by rulers which are placed at distances corresponding 

 to the desired thickness of the cake of glue. Tho linos formed by the grooves in the 

 bottom of tho box define the superficial area of each cake, where it is to be cut with 

 a moist knife. The gelatinous layers thus formed, must be dexterously lifted, and 

 immediately laid upon nets stretched in wooden frames, till each frame bo filled. 

 These frames are set over each other at distances of about threo inches, being supported 

 by small wooden pegs, stuck into mortise holes in an upright, fixed round the room ; so 

 that tho air may have perfectly free access on every side. Tho cakes must more- 

 over be turned upside down upon tho nets twice or thrice every day, which is readily 

 managed, as each frame may be slid out like a drawer, upon the pegs at its two 

 sides. 



The drying of tho glue is the most precarious part of tho manufacture. The least 

 disturbance of the weather may injure the glue during tho two or threo first days of 

 its exposure; should the temperature of tho air rise considerably, the gelatine may 

 turn so soft as to become unshapely, and even run through the meshes upon tho 

 pieces below, or it may get attached to the strings and .surround them, so as not to 

 bo separable without plunging tho net into boiling water. If frost supervene, tho 

 water may freeze and form numerous cracks in the cakes. Such pieces must IT im- 

 mediately re-melted and re-formod. A slight fog even produces upon glue newly 



