MECHANICS AND USEFUL AKT8. 45 



" Here we have conclusive data suggesting certain rules to be rigorously 

 adopted by all connected with steam boilers who would avoid mysterious 

 explosions : First, never feed one or more boilers with surplus water that has 

 been boiled a long tune, hi another boiler, but feed each separately. Second, 

 when boilers working singly or fed singly are accustomed, under high pres- 

 sure, to be worked for a number of hours consecutively, day and night, they 

 should be completely emptied of water at least once every week, and filled 

 with fresh water. Third, in the winter season the feed water of the boiler 

 should be supplied from a running stream or well." 



ON THE USE OF HIGH PRESSURE STEAM. 



The following views have been recently expressed by Mr. Fairbairn, the 

 eminent English engineer, on the use of high pressure steam for economic pur- 

 poses : 



" Taking into consideration the superior economy of high steam, worked 

 expansively, it is quite evident that in ah 1 future construction, either of boilers 

 or engines, we must look forward to the use of a greatly increased instead of a 

 reduced pressure of steam. Indeed, I am so thoroughly convinced of the 

 advantages inseparable from this application, as to urge upon you the neces- 

 sity of preparing for greatly increased progress, and greatly increased pressure 

 hi ah 1 the requirements, appliances, and economics of steam as a motive 

 power. It must appear obvious to every reflecting mind, that steam gene- 

 rated under pressure, and compressed into one-fifth or one-sixth the space that 

 it formerly occupied, and that again applied to an engine of little" more than one- 

 third the bulk, must be a desideratum in the appliance of an agent so power- 

 ful and so extensively used. Look at our locomotives at the present day, 

 and tell me whether we are or are not successfully progressing in effecting a 

 clearer alliance betv: 3en the two sister sciences of mechanics and physics ; and 

 tell me whether or not the community is secured equally weU from risk, and 

 greatly benefited by the change ? Let us calculate, for example, the duty 

 performed and the force applied to one of our largest class of locomotive 

 engines, travelling with a tram at the rate of 45 miles an hour, and we shall 

 find the amount of power given out to exceed that of 700 horses, or as much 

 as would be required to drive the machinery in some of our largest factories. 

 And why not work our factories upon this principle ? and why not propel our 

 largest ships by engines of this description? There is no reason why it 

 should not be done, and that with greatly increased economy, by introducing 

 a well directed system of condensation along with that of highly attenuated 

 steam." 



THEEMOGEXIC ENGINE. 



The above name has been given to an arrangement invented by Messrs. 

 Beaumont & Mayer, for producing heat sufficient to generate steam capable of 

 application to practical purposes by mere friction, 



The construction is simple enough. A boiler is made, traversed by a coni- 

 cal tube of copper. 30 inches diameter at the top, 35 inches at the bottom, 



