Polytechnic Association Proceedings. 791 



which consists of a sort of a burrette of India rubber furnished 

 with a tube of the same substance, a flash of three or four litres 

 capacity, and an air-pump which exhausts by means of a flexible 

 tube. By the use of this apparatus he removes the principal cause 

 of danger from amputations. 



HINGE MACHINE. 



The machine for making wrought-iron and brass-butt hinges, 

 invented by Messrs. Evrard and Boyer, of Paris, France, has lately 

 been brought to this country. Sheet iron or sheet brass is employed 

 of proper thickness. The hinges are made complete for market in 

 one single machine. Two strips of metal enter the machine on one 

 side from coils; on the opposite side is placed a coil of commercial 

 wire, which enters and forms the hinge rivets; the screw holes and 

 countersinks all being made in one operation. One hundred hinges 

 of the smallest size leave the machine per minute, in a condition to 

 be packed for market. One machine will make five different sizes 

 of butts — four-inch hinges being made at the rate of from twenty- 

 five to thirty per minute. 



LIGECTING GAS BY ELECTRICITY. 



Mr. Samuel Gardiner has just placed his electro gas-lighting 

 apparatus in the picture gallery of A. T. Stewart, Esq., it being a 

 part of the magnificent mansion which he is soon to occupy on the 

 Fifth avenue. The number of burners is three hundred and twenty- 

 five. The room was instantaneously lighted on the evening of the 

 19th ult., and was decided by Mr. Stewart, Mr. Kellum, the archi- 

 tect, and others present, to be a perfect success. From the street 

 the view was magnificent, the reflected light being seen at the dis- 

 tance of several blocks. On turning the gass off and on, the effect 

 was like that of repeated flashes of lightning. In the Gardiner 

 machine each burner is lighted by means of a platinum wire, made 

 red hot by means of an electric current. 



COPPER AMALGAM. 



This amalgum, used in the reproduction of etched and engraved 

 plates, is made by mixing mercury and pure powdered copper in a 

 small quantity of nitrate of mercuiy. Lowe obtains powdered cop- 

 per by adding to a saturated solution of sulphate of copper [cup- 

 mazot), an equal quantity of hydrochloric acid {thalad), and placing 

 in the mixture thin strips of zinc, when hydrogen gas is evolved 

 and a porous mass remains, which falls into powder on being 



