142 THEORY OF CONSTRUCTION AND SCIENTIFIC DESCRIPTION 



The method of calculating the power of the press, as well as every 

 other particular respecting it, has been fully exemplified in the fore- 

 going theory ; it is hence unnecessary to dwell longer on the subject : 

 we shall therefore conclude our description of the press, and proceed 

 with that of the Hydrostatic Bellows, which depends upon the same 

 principle, viz. the quaqua versum pressure of non-elastic fluids. 



2. THEORY OF CONSTRUCTION AND SCIENTIFIC DESCRIPTION OF THE 

 HYDROSTATIC BELLOWS. 



149. In the preceding pages we have developed the theory and 

 exemplified the application of the hydrostatic press ; and furthermore, 

 in order to render the subject as complete as possible, we have given 

 a minute and comprehensive description of its several parts, and for 

 the purpose of guiding the practical mechanic in its erection, the 

 instrument is exhibited in its complete and finished state, accompanied 

 by the forcing pump and all its requisite appendages. 



The next subject, therefore, that claims our attention, is the 

 Hydrostatic Bellows, an instrument of very frequent occurrence in 

 philosophical experiments ; it is chiefly employed in illustrating the 

 upward pressure of non-elastic fluids and the hydrostatic paradox, 

 and consequently, it depends upon the same principle as the hydro- 

 static press, admitting of a similar, but a more concise mode of dis- 

 cussion and illustration. 



150. The Hydrostatic Bellows consists of a tube or pipe FEI, of 

 very small diameter, and of any convenient length 



at pleasure, connected by means of the elbow at ^ 

 i, with a cylindrical vessel whose vertical section 

 is CDGH, and whose sides are made of leather 

 like a common bellows, represented by the waving 

 lines AmD and BWK; the upper and the lower 

 surfaces AB and DC, being formed of circular 

 boards corresponding to the cylindrical form of 

 the vessel. 



When the bellows is empty, it is manifest that the boards A B and 

 DC are very nearly in contact, and would be completely so, but for 

 the leather sides forming into folds and preventing a coincidence: 

 in this state, when water or any other incompressible and non-elastic 

 fluid, is poured into the tube, it flows into the bellows and separates 

 the boards ; a heavy weight as w is then placed upon the upper 



