136 Chronicles of Science. [Jan., 



the slit in the jet, producing a clear sheet. The slit is placed in 

 such a manner that the sheet presents a horizontal surface, and 

 this will easily cut the flame of a candle, showing a perfect section. 

 The hot gases and carbonaceous particles are carried off by the 

 water. On placing the eye above the hollow cone, the luminous 

 wall, &c, can be distinctly seen. Sections may easily be made 

 near the wick or near the point; nothing hinders observation, 

 which may be prolonged at pleasure, and a lens may be used if 

 desired. If a current of air be caused to come out of the slit by 

 bellows, an invisible sheet of air is formed which is also very con- 

 venient for making a section of flame. Close observation is quite 

 possible, for the aerial current prevents the heated gases from 

 reaching the eyes, and a lens may be used as in the former case. 

 The flame forms a cone, whose luminous walls are extremely thin, and 

 their size can be plainly seen. A platinum-wire may be introduced 

 across the section ; and on being plunged as far as the wick it will 

 remain unreddened in the dark interior of the cone. If a jet of gas 

 produced by a fishtail burner be cut, the luminous fan will be found 

 to consist of two brilliant blades, between which there is a narrow 

 obscure space. The blades are at a greater distance apart, and the 

 dark space is wider towards the end of the fantails ; M. Dufour 

 suggests that this method might be of service in the chemical 

 analysis of flames. 



Mr. Spence has made public an apparent paradox in the 

 science of heat, whereby he is enabled to raise a higher temperature 

 in certain solutions, by steam of 212° Fahr. He selected a solution 

 of a salt (nitrate of soda) having a high boiling-point — about 

 250° F. The nitrate of soda was placed in a vessel surrounded by 

 a jacket ; steam was let into the intervening space, until a tem- 

 derature of nearly 212° F. was obtained; the steam was then shut 

 off, and an open pipe immersed in the solution, and steam from 

 the same source was thrown directly into the liquor ; in a few 

 seconds the thermometer slowly, but steadily, moved, and minute 

 after minute progressed, until it touched 250° F. This unexpected 

 fact has become to the author of immense practical value. As a 

 corroboration of the theory which seems to explain the apparent 

 paradox, the author finds that the temperatures of his solutions are 

 in the exact ratios of their specific gravities, and have no con- 

 nection with the temperature of the steam, which never exceeds 

 212° F.. The greater the specific gravity of his solutions, the 

 higher the boiling-point ; and therefore, whatever the boiling-point 

 of the solution in water of any salt, to that point, or nearly, will 

 steam of 212° F. raise it. 



The annoyance which arises from the bumping of certain liquids 

 when submitted to distillation or boiling has often attracted the 



