Rev. J. B. Emniett on Solids and Liquids. 4 11 



leaks much ; and when such defects have existed in a boiler, 

 Mr. Taylor as well as myself has doubtless observed the es- 

 cape of large quantities of steam through the stacks : of course 

 the water in such cases does not undergo decomposition. 



The sudden bursts of flame from the chimneys of steam- 

 engines when observed at night, are in my opinion much 

 more satisfactorily accounted for, by supposing the flame to be 

 carried furdier up the flue at some times than at others, by 

 the action of gusts of air, which always operate more or less. 

 This is perhaps more frequently observed on die chimneys of 

 founderies or tin-smelting houses, than on those of steam-en- 

 o-ines ; and we are very sure that in the former cases no explo- 

 sions ever obtain. I am, &c. 



March 10, 1827. W. J. Henwood. 



^^ We liave received a communication on this subject 

 from Mr. J. Moore of Bristol, in which he states that steam- 

 engines have often exploded on their being stopped ; and that 

 the immediate cause of explosion, in these cases, is probably an 

 additional strain on the boiler from within, produced by the 

 steam, which previously had a free passage, being prevented 

 from escaping anywhere but at the safety-valve ; the aperture 

 of which, compared with the content of the cylinder, into 

 which the steam passed before, is very small. Mr. Moore 

 also suggests, for the purpose of obviating accidents from such 

 a cause, the application of a large valve on the tube, adjacent 

 to the part where the steam is prevented from passing to the 

 engine. — Edit. 



LXXXI. On the Physical Construction of Solids and Liquids. 

 By the Rev. J. B. Emmett*. 



THAT die particles of liquids do not touch each other, is 

 universally allowed, because the change of volume of 

 which all li(juids are susceptible by changes of temperature, is 

 greater than any that can result from any possible alteration 

 in the arrangement of condguous spheres. Besides, since the 

 particles of which a liquid is composed are inequilibrio be- 

 tween two ecjual forces acting in opposite direcdons, they can 

 occupy but one order of arrangement ; i. e. as Newton proved, 

 two riglit lines joining die centres of three adjacent particles, 

 must form an angle of G0° ; were they not thus balanced in the 

 point of e(|uihbriuni of two equal and opposite lorces, they 

 could not possess dieir observed freedom of motion. So long, 

 therelbie, as a body is in a liquid state, there can be neither 



- ('oiiiiiiiiiiiciilc'il l).v llic Aiilhor. 



r; (i 'j expansion 



