370 EXPLANATION OF THE PLATES. 



PLATES XLVII. AND XL VIII. 



SAMUEL HALL'S IMPROVEMENTS ON STEAM ENGINES. 



Some very important improvements have been made on the steam engine by Mr. 

 Samuel Hall, of Basford, near Nottingham, for which he has obtained letters patent. 

 The principal objects of these improvements are to supply the boilers with pure 

 distilled water (thereby increasing their duration,) to effect an economy of fuel, and to 

 produce an increase of power. These objects, it is stated, are obtained by condensing 

 the steam by the external application of cold water, instead of injecting it into the 

 steam. The improvements have been in successful operation for upwards of four 

 years, having been applied to several land engines and to a considerable number of 

 marine engines, varying from 70 to 320 horse power each pair, and there is every 

 probability that they will generally supersede injection engines. As Mr. Watt 

 attempted to condense steam without injecting cold water into it, and came to the 

 conclusion that it was impossible to effect a sufficiently rapid condensation of steam, 

 for steam engines worked by vacuum, by means of the external application of cold 

 water, and as many other persons have also failed in similar trials, it is desirable to 

 ascertain the means adopted by Mr. Hall, and for this purpose we give the following- 

 extract from the specification of his patent, shewing wherein his invention consists* 

 and the causes of his succeeding in obtaining a desideratum which others have 

 attempted without success. 



EXTRACTS FROM THE SPECIFICATION. 



" The objects of my invention (which invention I confine to steam engines worked 

 by a vacuum produced by condensation) are to condense without injection water 

 (for the purpose of creating as good a vacuum as is obtained and well known in 

 injection engines) the steam which passes through the engine for the working 

 thereof, and also to condense for the most part (if not wholly) that portion of steam 

 which usually escapes into the atmosphere through the safety valves when the 

 pressure of the steam in the boiler is too high during the working of the engine, in 

 order that the water resulting from the condensation of such steam may be returned into 

 the boiler. And also, further to supply so much more distilled water to the boilers 

 of the above mentioned description of engines as is required to supply and replace 

 any waste that may take place in the working thereof, in order to avoid the intro- 

 duction of any water (into the boilers) containing saline or other extraneous matters. 



