3Q4 New Engine. 



and muriatic acid. Tin produced Libavius's liquor, mer- 

 cury, corrosive sublimate, silver and lead, horn silver, and 

 horn lead. Iron, a beautiful, volatile, crystallized substance 

 which gave the red muriate of iron on the addition of water. 



Mr. Davy also found that oxvmuriatic gas decomposes 

 the metallic oxides at a heat below redness ; — those of the 

 volatile metals more easily than those of the fixed metals, 

 and protoxides more readily than peroxide?. Mr. Davy 

 notices two beautiful experiments on the agency of oxy- 

 muriatic gas on white oxide of arsenic, and black oxide of 

 iron* In these cases, no oxygen was evolved, the portion 

 separated from one part of the oxides combined with the 

 other part, and the products were butter of arsenic and 

 arsenic acid, and ferruginous sublimate and red oxide of iron. 



Mr. Davy notices an experiment in which he decom- 

 posed the gray oxide of tin by muriatic acid gas. In this 

 case, water rapidly separated and Libavius's liquor was 

 formed. 



Mr. Davy conceives that these new inquiries confirm all 

 the conclusions he has drawn in his recent paper on " Oxy- 

 muriatic Acid, &c." 



LXXIII. Intelligence and Miscellaneous Articles. 



^ NEW ENGINE. 



An engine has been lately invented by Mr. Taylor of Hol- 

 well, Engineer to the Tavistock Canal, which may be put 

 into motion either by water or steam, without any alteration 

 in its construction or in any of its parts. It is extremely 

 simple, and may be erected at a moderate expense. Its 

 power when worked by water is, as in other hydraulic ma- 

 chines, in proportion to the quantity employed and height 

 of the fall. When steam is substituted, the area of the 

 piston determines the effect. 



It may probably be a valuable machine in cases where a 

 falling stream may be had equal to useful purposes at one 

 period of the year, and deficient in a proper supply in dry 

 seasons. Many mines and manufactories are in this situa- 

 tion, and might by a single engine of this sort work un- 

 interruptedly, saving the expense of coal when the stream 

 of water was sufficient, and using the boiler only when the 

 supply of water fell short. It is of the kind of hydraulic 

 machines usually called Pressure Engines; various con- 

 structions of which have been attempted, but none have yet 

 been very successfully made, at least upon a large scale. 



The 



