Mr. Howldy on Combustioyi by the Electric Spark. 267 



on matter, by the omnipotent and all-wise Creator ; and they 

 strove by every means in their power to subvert their super- 

 stitious belief in the agency of demons of fire and earthquakes, 

 whom it was necessary to propitiate by penances, sacrifices 

 and privations, mingled with habitual slavish fear. 



We conclude by expressing the hope that we may soon be 

 favoured with other productions, similar to that from which 

 we have now made such copious extracts. We trust that all 

 who may peruse these remarks, will be inclined to read the 

 volume of the missionaries. Besides what relates to the mis- 

 sion, they will find very interesting notices of the scenery of 

 the country — of its vegetable productions, and of the manners 

 of its inhabitants. It appears that on one occasion " the na- 

 tives produced fire by rubbing two dry sticks together." 



XXXIX. On effecting Combustion by the Electric Spark. By 

 Mr. Thomas Howldy. 



To the Editor of the Philosophical Magazine and Journal. 



Sir, 



A BOUT the middle of the eighteenth century it was dis- 

 -^*- covered by Dr. Ludolf of Berlin, that some combustible 

 bodies could be set on fire by means of the simple electrical 

 spark. The first substance that he inflamed by the agency of 

 the spark was the ethereal spirit of Frobenius (sulphuric 

 aether ?), the experiment being performed at the opening of 

 the Royal Academy of Berlin, and " in the presence of some 

 hundreds of persons." This interesting effect of the electric 

 spark excited considerable attention to this part of the inci- 

 pient science of electricity ; and several other German philo- 

 sophers, after repeating the experiment of Dr.Ludolf, pur- 

 suing the discovery, inflamed by the same agency other in- 

 flammable liquids ; and even oil, pitch, and sealing-wax, when 

 these substances had been heated nearly to the point of spon- 

 taneous combustion. The results thus obtained by the Ger- 

 mans were only the realization of a conjecture of M. Du Fay, 

 a French philosopher, who had several years before conceived 

 that the electric fluid possessed the property of inflaming com- 

 bustible substances, though he was not able at the time to de- 

 monstrate the fact. 



Those important experiments appear to have been effected 

 during the year 1 744 ; and the English philosophers having 

 obtained the necessary information concerning them, pro- 



2 L 2 ceeded 



