Chemical and Physical Notes 



53 



lamp A, the steam generator B, the steam vessel or distilling 

 tube C, and the thermometer D. The lamp shown is one of 

 a French pattern, sold with the Rfahaud a double flamme 

 forcee of smallest size. It holds about 250 c.c. of spirit, and 

 gives a flame powerful enough to work a much larger flask. 

 The steam generator B is a flask made of spun copper, and 

 of 500 c.c. capacity. A suitable charge is 300 c.c. of water. 

 With such a charge, and heated by the French lamp, the 

 water boiled in six minutes at an expense of 12 grms. of 

 spirit. While keeping steam at the rate suitable for the 

 experiment the lamp consumed 21 grms. of spirit in fifteen 

 minutes, and evaporated 92 grms. of water. 

 It is obvious that where gas is available a 

 gas lamp may be used. 



A very convenient lamp, especially for 

 work out of doors, is the Swedish lamp for 

 burning petroleum or paraffin oil under 

 pressure, and with a blue flame. It is 

 particularly useful when larger steam gene- 

 rators are used, such as the metal flasks 

 made for the Napier's coffee machines, 

 used in restaurants. One of the ordinary 

 size holds 2 litres, and is a most useful 

 article both in the camp and the laboratory. 



Another and very convenient form of 

 steam generator is shown in Fig. 3. A is 

 a tubulated bell-shaped vessel of tinplate, 

 which passes inside the slightly larger receiver B, which 

 holds the water to be boiled. The rest of the apparatus 

 is the same as in Fig. I. This form of steam generator has 

 many advantages, and in travelling the lamp can be stowed 

 inside it. 



The most important part of the apparatus is the steam 

 tube or vessel C. The following are the dimensions of one 

 which has been a good deal in use (Fig. 4). 



The wide part (a) is 160 mm. long, and 41 mm. in diameter. 

 The part (b) making connection with the steam generator is 

 60 mm. long, and 9-5 mm. wide. The upper portion (c) is 



