PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 487 



Mr, Johnson said he would get the desired information at the 

 Novelty Works, 



The Chairman said there was a species of Bitumen which 

 would answer the purpose required, and stated that 100'' would 

 not have much effect in melting it. He had used it in the gut- 

 ters of his house in the country, and also had it in use on vessels. 



Mr. Garvey. — A composition of beeswax and rosin would 

 answer, but would be of little use except in a certain tempera- 

 ture — neither too hot nor too cold. Davy of Dublin had invented 

 a material composed of Asphaltum and Gutta Percha, which was 

 the best in existence for that purpose. It was flexible and must 

 be used in a warm state. 



Mr. Churchill stated that he had used it, and found that the 

 gutta percha in commerce was not pure enough for that purpose. 

 He alluded to a composition which he made by infusing rosin in 

 a crucible along with some beeswax, and then adding some starch 

 by stirring it in. It adheres very firmly to glass. He had used 

 it for that purpose last winter, and found that it had adhered 

 most rigidly ever since. He had also substituted lard for the 

 beeswax, and had even instilled ether into it, and found it very 

 good. 



Mr. Garvey had used it, and stated that the more beeswax was 

 used, the less brittle it became. He had also used plaster of paris 

 mixed with wax and rosin, and stated that stone cutters use 

 pounded stone or stone dust mixed with beeswax to mend broken 

 pieces, and they found that it answered all purposes. It is not 

 reliable in heat of a stronger temperature than 120'', In a heat 

 of 130'' or 150*^ it would not be in any way reliable. 



The Chairman suggested the use of boiled linseed oil with 

 rosin and beeswax. He stated that it could be used at first with 

 a brush, and afterwards it became very tenacious. He had used 

 it on the limb of a tree. It could be bought of the Franklin 

 Coal Company, 



STEAM CUTOFF. 



Mr, Hedriek said it was understood that he was to take the 

 theoretical part of the subject, and wished, if there were any 

 gentlemen present who intended to speak on the facts of the 

 case, that they would do so. 



Robert Humphries said that the chief engineer of the Metro- 

 politan Flour Mills, in Cherry street, had stated to him that he 



