Polytechnic Association. 623 



Dr. Yan der "Weyde considered it a mistake to make coffee in a tin 

 coffee-pot, and recommended the porcelain lined coffee-pot. 



Mr. Fisher added that it was a mistake to make the coffee-pot with 

 a nozzle, which could not be kept clean. 



The President read the following items of scientific news : 



/ 



I. A Steam Hygrometer. 



This instrument, invented by Leiscester Allen, is designed for 

 the purpose of measuring the amount of moisture in steam gen- 

 erated in ordinary boilers; the terms "wet steam" and "dry 

 steam " being used to distinguish steam holding particles of water 

 from that which has been completely volatilized. The construc- 

 tion of this instrument is based upon the fact that the amounts of 

 heat in a pound of water at 212° Fahrenheit and a pound of steam 

 at the same temperature are well known. To determine the amount 

 of heat carried out of a boiler, an apparatus has been devised, which 

 consists of a scale-beam with a platform and a thickly felted water- 

 chamber at one end, and a counterpoise at the other, having a sliding 

 weight indicating pounds and half-pounds. The walls of the water- 

 chamber are made of thin tinned sheet copper, there being two shells, 

 between which felting, 1^ inches thick, is placed. A felted cover is 

 also provided, through which is inserted a standard thermometer 

 having a large bulb, and easily read in fifths or degrees. A finely 

 perforated coiled copper pipe rests upon the inner floor and passes 

 out at the lower part of the side wall of the chamber. This is the 

 steam induction pipe. The lower part of the chamber has the shape 

 of an inverted tunnel, to which is attached an escape-pipe. Both 

 pipes are provided with cocks. A small funnel in the cover, also 

 provided with a cock, completes the apparatus. To use this instru- 

 ment, five pounds of water are placed in the chamber and raised to 

 80° Fahrenheit, by allowing steam to pass through the coil. The 

 surplus water is drawn off, leaving five pounds of water at 80°, con- 

 taining 400 units of heat. The sliding weight is then placed at the 

 5-| pounds notch, and the steam to be tested is allowed to flow in 

 until the scale-beam is balanced. The influx of steam is then stopped, 

 and the thermometer is read. With these data the amount of water 

 in the steam is calculated. 



II. To Detect Sulphur in Coal Gas. 

 Ulex has published a simple process of detecting the presence of 

 sulphur in ordinary illuminating gas. The flame from the gas is 



