Yates's water-proof glue or cement

Now here's a use for Mild Ale that I would never have thought of: making glue.

"YATES'S WATER-PROOF GLUE OR CEMENT.

Take of the best Irish glue, four ounces; and of isinglass, two ounces: these must be dissolved in mild ale (not stale), over a slow fire, in a common glue-kettle, to the consistence of strong glue; when one ounce and a half of wellboiled linseed oil must be gradually added, and the whole well incorporated together by stirring. To increase the. strength of the glue, more isinglass may be added.

This cement is applicable to the joints of wood, in every branch of manufacture; as also to joining earthenware, china, and glass ;—care being taken to press the parts well together, and to allow them sufficient time to set .

The cement, when cold, and made into cakes, assumes the appearance of India-rubber; and, like it, is elastic. It may at any time, when wanted for use, be dissolved, by a gentle heat, in any proper iron or glazed earthen-vessel; first putting into it a little mild ale, to prevent it from burning at the bottom of the vessel; and adding more ale, to bring it to a proper consistence for use. To cement leather together, for harness, bands for machinery, &c, having prepared the joints in the usual way, as if for sewing, apply the cement while hot, laying a weight upon each joint, as it is made: let them remain six hours before using, and the joints will then become nearly as firm as if made of one entire piece of leather. An excellent cement for stopping leaks in casks, &c. may be made by putting a little tow to the other ingredients. The Editor had this receipt from a Mr. H. Yates, in the year 1811."
"The Technical repository" by T. Gill, 1822, page 373.

Like India rubber? It sounds weird. Must have had a nice beery smell, though. I wonder why isinglass was included in the recipe?