Perkins'' Steam Engine. 41 



of my invention ? If it is not new, to have a pressure of 

 1000 lbs. to the square inch, on one side of the piston, while 

 on the other side of it, all resistance is taken away by a va- 

 cuum, and this produced, without an air pump, or any more 

 water than is used in generating the steam ? If it is not 

 new to have invented a metallic piston, which requires no 

 lubrication, and yet is as tight as the piston of an air pump ? 

 If it is not new to have applied Sir Humphrey Davy's zinc 

 protectors to steam cylinders, to prevent oxidation ? This, I 

 found, took place in my cylinders, when the engine was not 

 at work, after I found that I could dispense with oil. If it 

 is not new to dispense with the eduction valve, and eduction 

 pipe, having no other than a small induction valve, and that, 

 so constructed, as to neutralize the pressure, requiring no 

 oil, and very little power to open, and to close it ? If it is 

 not new, to allow steam to escape at an opening, 250 time^ 

 larger than the steam pipe ? All this has been effected as 

 our friend Lukens can avouch, he having witnessed all these 

 facts, as well as myself. And lastly, if it is not new, to have 

 discovered, that steam may be generated, although in con- 

 tact with the water, at all temperatures, without producing 

 corresponding elasticity? 



As soon as my last patent is specified here, I will forward 

 it to you, together with the drawings, not only for your in* 

 spection, but with a request, that you will forward them to 

 Washington, as a petition to obtain a patent, will accompa- 

 ny them. 



I herewith send you a paper, " On the Explosion of Steam 

 Boilers, &c." This paper I have not yet published here, as 

 it might lead to the discovery of my method of correcting the 

 evil arising from generating surcharged steam, before my 

 patent is specified ; but as this will be secure, in a very short 

 time, you are requested, if you approve it, to publish the pa- 

 per in your interesting Journal, as I am anxious for its early 

 appearance in my own country. I have, in confidence giv- 

 en a copy to Dr. Wollaston, to Mr. Faraday, and to several 

 engineers, whom I could trust, and who all agree that it as- 

 signs the true cause of explosions. I long to see, and to 

 converse with you, and my other really scientific friends in the 

 United States, on this and other interesting points, connec- 

 ted with my engine. 



I have had much interested opposition to contend with, 

 since my residence here ; but some of the best men in the 



Vol. XIII.— No. U 6 



