318 Cooper'' s Rotalive Piston. 



minute, and require twenty men to work them. The price 

 and power of the other engines do not material!)' vary from 

 the New-York engines. Another defect, or objection, is the 

 weight, which uniformly exceeds a ton, and in some approach- 

 es nearly two tons. They are likewise liable to be more 

 or less out of order, and the expense of keeping them in re- 

 pair is not inconsiderable. 



Aware of the disadvantages of the engines now in use, 

 and desirous of benefitting others, while advancing our own 

 interest, we have devoted considerable time and attention in 

 constructing fire engines on a principle entirely new. This 

 principle was invented by Mr. Cooper, a partner in our con- 

 cern, and we have made a number of engines, all of which 

 have equalled our most sanguine expectations, and placed their 

 utility beyond the shadow of a doubt. Simple in construc- 

 tion, and comparatively light, the expense bears but a small 

 proportion to that of those now in use. Our general rule is to 

 afford them for about one half the price which equal sizes of 

 the old ones are sold for ; and although our profits at this 

 price are not large, we hold it to be the duty of proprietors 

 of a patent, where the invention is of great public utility, to 

 fix such prices as will enable all to purchase. 



The following is a summary of the advantages claimed by 

 the inventors and proprietors for their engine. 



The simplicity of its construction, its rotary motion, its 

 admirable compactness and unquestioned durability, are ad- 

 vantages, of no slight importance, over those on the old prin- 

 ciple, which this machine possesses. Independently of these 

 advantages there are others of still greater magnitude. It 

 will raise and discharge double the quantity of water, in a 

 given time ; or, in other words, it requires the application of 

 only one half the poiver^ to produce the same efl'ect. It dis- 

 charges a more dense column. It is as little affected by the 

 frosts of a northern winter as by the heat of summer : and 

 it can be made for one half the expense. 



It will raise double the quantity of water. 



The fact is self-evident, that in working the old engines, 

 to discharge the chamber or cylinder once, the piston must 

 pass twice through it : an ascending stroke to create a va- 

 cuum, and a descending one to force the water. Half the 

 lime is consequently lost. In the rotative, on the contrary, 

 it is equally evident, that a continued vacuum is created, and 



