82 WISCOKSIJT ACADEMY SCIE2TCES, ARTS, AND LETTERS. 



would then gradually spread over the surface of the oil hi an en- 

 larging circle, and no sudden flash would be observed, ar,in the case 

 when a lamp is broken containing oil heated above the temperature 

 at which it evolyes a combustible vapor. It is certainly to be hop- 

 ed that these perfectly safe oils will soon come into general use. 

 The lamp in which kerosene is burned, often has an important bear- 

 ing upon the temperature of the oil which is contained in it. I 

 can not better convey an idea of the effect of the lamp upon the 

 temperature of the oil, than to quote from a report upon the sub- 

 ject, submitted to the Metropolitan Board of Health, in 1870, by 

 Professor C. F. Chandler, of Columbia College, and chemist to the 

 board. He says, " in continuing the investigation with regard to 

 dangerous kerosene, it was thought a matter of importance to 

 ascertain the temperature to which the oil is heated in lamps while 

 thej' are burning, as a knowledge of this point is obviously a pre- 

 liminary to the establishment of a proper standard for safe oil. To 

 this end twenty-three ordinary lamps were purchased. Eleven were 

 of metal, mostly brass; twelve were of glass. They were filled 

 with the same oil and allowed to burn for seven hours; the tem- 

 perature of the room during the experiment was nearly constant, 

 varying from 73° to 74:° Fah. The temperature in the eleven metal 

 lamps vai'ied from 76° to 100°, the average being 86° Fah. The 

 temperature in the twelve glass lamps varied form 76° to 86°, the 

 average being 81° Fah. The average temperature of all the ob- 

 servations on all the lamps was 83° Fah. 



These experiments show, that an oil which does not give ofiP an 

 inflammable vapor below 100 ° F., may be regarded as perfectly 

 safe. They also show that the average temperature of the oil in 

 the lamp is about 8 ° above the temperature of the room in which 

 it is burning, hence if the temperature of a room in which an oil 

 is burning is 74 ° , and the flashing point of the oil is 80 ^ , a vapor 

 is constantly passing off, and there is danger, upon suddenly cool- 

 ing the lamp, of an explosion. 



Testing the oil is a very simple operation. A rough method of 

 detecting dangerous kerosene is to pour out a small quantity of the 

 oil into a saucer, and attempt to ignite it with a lighted match. If 

 the flame is not at once extinguished, on being plunged beneath the 

 surface of the fluid, the oil is highly dangerous, and should at once 

 be consumed. By this means cheap burning fluids, usually bearing 



