42 ANNUAL OF SCIENTIFIC DISCOVERY. 



But 0:1 turning a cock the escaping steam is found to be white and cloud-like. 

 This is due to the cooling effect of the air, which mixes with and apparently con- 

 denses it. Mr. Storms's experiments lead him to the conclusion that the volume 

 of the whole is increased by the combination, and this to a very considerable de- 

 gree, as high, under favorable circumstances, as 75 per cent., and consequently 

 affording a corresponding increase of efficiency in an engine. If common air be 

 compressed and introduced at an ordinary temperature into a vessel contain- 

 ing steam at the same pressure, the following effects may be anticipated : On 

 the one hand, a portion of the steam will be condensed and changed to water, 

 which will diminish the pressure ; but on the other hand, the air will be 

 heated and expanded ; and these two effects may be supposed very nearly, if 

 not exactly, to balance each other. But the experiments alluded to indicate 

 a very decided increase of volume, provided there is a sufficient difference of 

 temperature. If pure transparent steam be mingled with air previously 

 heated to the same degree, none of this expansion is experienced, and it be- 

 comes a question how to compress air in a pump and convey it in a cold state 

 into a heated cylinder. 



Mr. Storms avoids the solution of this difficult problem by allowing the ah* 

 to mix thoroughly with the steam at any temperature it may chance to have, 

 cooling it afterward by expansion. In other words, he mixes hot or warm 

 air with the steam in the steam-chest, and does not expect the mixture to as- 

 sume the cloud form until it commences to expand in the cylinder. The act 

 of expanding cools both steam and air, but in very different proportions. 

 Pure steam, of a high pressure (say 60 pounds), has a temperature of about 

 310 F., and if cut off at half-stroke, so as to double its volume by expansion, 

 cools down to only about 270, while air at the same temperature, if expanded 

 to the same extent, cools down to about the freezing point. Thus the com- 

 bined fluids may readily be compelled, by expansion, to assume the form of 

 cloud or vesicular vapor, if the presence of air at a different temperature be 

 the only condition necessary. To accomplish this object in an ordinary hori- 

 zontal engine, Mr. Storms has, in the instance above referred to, placed 'a 

 double-acting air-pump near the cylinder, and allows it to discharge into the 

 steam-chest, just above the valve. As the first portion of the stroke of the 

 pump is spent in simply compressing its contents, it is so timed that it will 

 begin to deliver with the commencement of the stroke of the piston. The 

 pump is enveloped in a jacket of cold water to keep it cool, and the air prob- 

 ably enters the steam-chest at a temperature of from 180 to 250 



A series of experiments have been lately tried at the Novelty "Works on a 

 tolerably large scale. The engine was run first with steam alone, and then 

 with the cloud combination, the resistance being constant in all cases. The 

 revolutions produced per Ib. of coal were as follows: steam 107, cloud 190; 

 showing a great advantage by the use of the cloud vapor. 



Mackenzie's Cui-off, A device for regulating the motion of steam en- 

 gines without the aid of a Governor, has been invented and patented by Mr. 

 P. "W. Mackenzie, of Jersey City, N. J. The arrangement is described by the 

 New York Tribune as follows : The valve is designed to close the steam-pipe at 

 or near its entrance to the steam-chest. It is capable of "cutting off" at any 



