Alcoholic Fluids, Oils, ^c. in Lamps. 61 



iqjon miaking the experiment, I found it succeed beyond my 

 most sanguine expectations.'" — " I found that the discharge of 

 yellow light depended greatly on the nature of the wick, and 

 on the rapidity with which the fluid was converted into va- 

 pour/' A piece of sponge, having a rough surface, was found 

 to constitute the best wick, and for converting the alcohol ra- 

 pidly into vapour, the heat of the wick-holder was increased by 

 a spirit-lamp ; or red hot wire gauze was brought into contact 

 with the surface of the sponge *. 



By these extracts, we are given to understand, that, when al- 

 cohol, " in its purity," is burned, it gives a yellow flame ; but 

 that, when alcohol, diluted with water, is burned, yellow light is 

 given out in greater abundance ; and the conclusion seems to be, 

 that, as moisture increases the quantity of yellow light during 

 the combustion of cotton, paper, &c. so water added to alcohol 

 has the same effect ; and that, on such occasions, the water acts 

 by causing, or by increasing the disposition to " imperfect com- 

 bustion." Admitting, however, that these views were established, 

 such questions as the following immediately present themselves : 

 What is imperfect combustion ? Is the presence of water essen- 

 tial or only accessary ? &c. This is a subject that might en- 

 gage the attention of some one of the many expert chemists of 

 the present day : there is certainly no want of interest, and 

 much precise information is still wanting. The few facts that 

 have been, or that may be, brought forward on the present oc- 

 casion, are submitted as a contribution, with the hope that they 

 may tend to promote investigation. 



The blue flame of diluted alcohol has, as formerly stated, a re- 

 gular form ; is steady as that of a well-adjusted candle, and the 

 combustion proceeds in silence; but, when burned with a wick, or 

 otherwise, so as to give a yellow Hght, the flame is very un- 

 steady, and the combustion is always accompanied with noise. 

 Whether this noise proceeds, in every instance, from actual ex- 

 plosions, may be uncertain ; but it is certain that when diluted 

 alcohol is exploded, by throwing it into a red hot fire, or by 

 other means, a profusion of yellow light is extricated ; and, when , 



* See Description of a Monochromatic Lamp, by David Brewster, LL. D. 

 &c. &c. published in the Transactions of the Royal Society of Edin., 1822. 



3 ' 



