360 History of Mechanical Inventions and 



and tight, even with the steam at the pressure of JOOOlbs. to the square 

 inch, than the joints of the low pressure condensing engines." — Newton's 

 Journal of the Arts, May 1827; p. 162. 



In the same Journal for July 1827 we find the following certificates; — 



** We, the undersigned, certify, that there are two low pressure steam 

 engines employed night and day in discharging the water which flows into 

 St Catherine's dock from the land springs, &c., and that one of them is a 

 .sixteen, and the other a ten horse engine. We also certify that Mr Perkins 

 has recently put up a small high pressure steam engine, the diameter of 

 whose piston is eight inches, and its stroke twenty inches, and yet we have 

 seen this engine pump the same quantity of water from the docks which 

 has been heretofore pumped by the other two. 



*' James Lamon. 



" Pearson Woodward. 



" Thomas Browne." 



** I, the undersigned, certify that I have put up Mr Perkins's high pres- 

 sure safety engine, and that what is stated by the above engineers is true, 

 and that it was done with only 42lbs. of coal per hour. Having been en- 

 gaged twenty-two years in making and putting up engines, principally in 

 Cornwall, it is not likely that I could be deceived as to the power and effi- 

 cacy of this engine, and I conscientiously believe that two-thirds of the 

 coals used in this country might be saved by the use of this engine. 



'' Henry Hornblower." 



** I, the undersigned, carefully weighed the coals, and placed them under 

 Mr Perkins's generator, and 42lbs. weight of coals only were used per hour. 

 I also certify that what is stated by the above engineer respecting the 

 work done is true. " W. Herne." 



Mr Perkins is of opinion that the two low pressure engines could not 

 have been worked up to their full power, though they used the full quan- 

 tity of coal, 3;j bushels per hour. But admitting that they worked only at 

 two-thirds of the power, there would be a saving of three-fourths of the 

 coal consumed in low pressure engines, by the employment of Mr Perkins's 

 new principle. 



3. Account of a new Register Raiu'Gage. By B. Bevan, Esq. Civil 

 Engineer. 



The collecting vessel of this rain-gage has the form of an inverted cone, 

 with a base twelve inches in diameter. From the lower end of this vessel 

 passes a tube three-fourths of an inch in diameter, to the receiving cylin- 

 der, six inches in diameter, and thirty-six inches deep. In the receiving 

 cylinder there is a copper float about nine and a half inches in diameter, and 

 two inches high, having a socket on the middle of the upper side to sup- 

 port a light rod of deal about five feet long, near the upper part of which 

 is fixed a small frame with friction rollers to support a black lead pencil. 

 The pencil is kept upon the roller by a small weight, and is also pressed for- 

 wards by another small weight against a sheet of paper, which is fastened 

 upon a brass cylinder two feet long, and five inches in diameter. The 



