474 TRANSACTIONS OF THE 



about house. SucK a tiling had long been known and used In Euglancl, and 

 he improved on the recipe and introduced a superior article. 



Mr. Seeley. — Common glue dissolved in any acid will always keep liquid. 

 It will not have as great adhesive force, however, as common glue. There 

 is a marine glue on exhibition—said to be made of glue and India rubber 

 ■ — which does not answer to the qualities ascribed to it by the inventor. 

 Boxwood being expensive, some experiments were tried to stick a veneer 

 of boxwood on a block of cheaper wood for engraving. On wetting the 

 compound block, however, the pieces separated. Shellac is perhaps the 

 best marine glue we have. 



Mr. Butler.— 'I have found great difficulty in making emery wheels for 

 our works, but I now learn that a party has made such wheels solid of 

 emery, cemented together with vulcanized India rubber. Our plan was to 

 use an iron core, and fix the emery powder to its surface with glue. A 

 little salammonia helps the glue to adhere to the iron. 



Mr. Stetson. — Very few understand how to use glue. The wood should 

 be heated before the glue is applied, both to expel moisture and to prevent 

 the glue chilling too soon. Thin glue should be used and be applied in 

 repeated coats, each being allowed to dry well before another is applied. 

 The last coat then should be of strong glue, and the job will be well done. 

 It will stand a strain of from 300 pounds to f 00 pounds to the square inch. 



Mr. Garvey considered it an error to use thin glue for joints, &c. It is 

 well established that a viscid liauid is more sensitive to capillary attraction 

 than a thin one. This is shown in the florid complexion of those who have 

 thick rich blood, and in the sallow complexion of those with thin, watery 

 blood. The capillary blood vessels of the skin can take up the one and do 

 not take up the other. When well seasoned timbers with true joints are 

 fitted together with glue of a thick consistency, they invariably make good 

 work, at least in my experience. 



For purposes where glue is required to withstand moisture, it is cus- 

 tomary to boil the glue in linseed oil instead of water. The glue is steeped 

 over night, and the softened cakes are then boiled in linseed oil, using the 

 same amount of oil that would be used of water for other purposes. This 

 preparation is an excellent marine glue, and in extensive use. 



Mr. Hedgem-an said, I am a piano maker and in my business we require 

 the strongest and best glue, and we always use thick glue. 



Mr. Seeley.— There is a mineral paint on exhibition, but no explanation 

 of its peculiarities or chemical nature is given. Any other clay or dirt will 

 apparently answer as well for paint. 



Mr. Stetson.— For preventing rust there are two forms of paint now 

 being introduced pretty generally. Butcher's, of Philadelphia, and Ellery's, 

 of New York. Butcher uses India rubber, Ellery gutta percha ; but prac- 

 tically there is no dilFcrence between them. 



Mr. Haskell. — Ellery's has an advantage in using gutta percha. It drica 

 in about the same time as ordinary linseed oil and white lead, and gives a 

 good body for covering. 



