322 



BENJ. PIKE S, JR., DESCRIPTIVE CATALOGUE. 



- 37a length is seven feet six 



inches, one foot of which 

 is occupied by the smoke 

 chamber, making the ac- 

 tual length of the boiler 

 six and a half feet ; ils 

 diameter three and a 

 half feet. The furnace, 

 D, and ash-hole, c, are 

 contained within the 

 boiler ; and are furnish- 

 ed with a metal screen 

 to be applied for the 

 purpose of excluding 

 the light during the pro- 

 gress of one class of 

 experiments; F is the 

 water gauge ; E, the 



feed-valve ; j J, are two tubes leading from the valves, K K, 

 to the two tubes, H ; A and i, are forty-six bent iron tubes, 

 terminating in jets, either half or the whole of which may 

 be opened by means of the lever, G G ; L, is a valve for 

 liberating steam during the existence of the maximum pres- 

 sure ; M, is the safety valve ; N, is a cap covering a jet, that 

 is employed for illustrating a certain mechanical action of a 

 jet of steam ; o, is the first portion of the funnel ; P, the 

 second portion, which slides into itself by a telescope joint, 

 so that the boiler may be insulated when the experiments 

 commence. The boiler is cased in wood. 



379. The next figure (379), 



T-~ which may be called the 

 prime conductor, but which 

 is not used for the purpose, 

 is a zinc case, furnished with 

 four rows of points. It is 

 placed in front of the jets, 

 in order to collect the elec- 

 tricity from the ejected va- 

 por ; and thus prevent its 

 returning to restore the equilibrium of the boiler. The 

 maximum pressure at the commencement of the experiments 

 is 80 Ibs. ; which gradually gets reduced to 40, or lower. 



