CONTENTS. Xlll 



The Hydrostatic Weighing Machine introduced, described, and investigated, 

 art. 160, pages 151, 152, and 153. Practical rule and example for ditto, art. 161, 

 page 154. Quantity of ascent above the first level determined, practical rule and 

 example for ditto, art. 162, pages 154 and 155. Concluding remarks, art. 162, 

 page 155. 



Quaquaversus pressure of incompressible fluids illustrated by experiments, pages 

 155-160. 



CHAPTER VII. 



OF PRESSURE AS IT UNFOLDS ITSELF IN THE ACTION OF FLUIDS 

 OF VARIABLE DENSITY, OR SUCH AS HAVE THEIR DENSITIES 

 REGULATED BY CERTAIN CONDITIONS DEPENDENT UPON PAR- 

 TICULAR LAWS, WHETHER EXCITED BY MOTION, BY MIXTURE, 

 OR BY CHANGE OF TEMPERATURE. 



Preliminary remarks on density, pages 161, 162, and 163. The alteration of 

 pressure in consequence of a change of temperature determined, art. 163, pages 

 163, 164, and 165. The chord in a semicircular plane on which the pressure is 

 a maximum determined, on the supposition that the diameter is in contact with the 

 surface of the fluid, and the density increasing as the depth, art. 164, pages 165, 

 166, and 167. Practical rule for ditto, art. 165, page 167. Example for illus- 

 trating ditto, art. 166, page 167. Construction of ditto, art. 167, pages 167 and 168. 

 The section of a conical vessel parallel to the base, on which the pressure is a 

 maximum, determined, the axis of the cone being inclined to the horizon in a given 

 , angle, art. 168, pages 168, 169, and 170. Practical rule for ditto, art. 169, page 170. 

 Example for illustrating ditto, art. 170, page 170. Concluding remarks on 

 compressibility, art. 171, page 171. The diameter of a globe determined, in 

 ascending from the bottom to the surface of the sea, on the supposition that the 

 globe is condensible and elastic, art. 172, pages 171 and 172. Practical rule for 

 ditto, art. 173, page 173. Example for illustrating ditto, art. 174, page 173. 

 Remark on ditto, art. 175, page 173. The depth of the sea determined, art. 176, 

 pages 173 and 174. Practical rule and example for ditto, art. 177, page 174. 

 Pressure on the bottoms of vessels containing fluids of different densities deter- 

 mined, art. 178, pages 174 and 175. Law of induction expounded, art. 179, pages 

 175 and 176. Example for illustration, art. 180, page 176. Another example 

 under different conditions, art. 181, pages 176 and 177. Pressure on the inner 

 surface determined and compared with that upon the bottom, art. 182, pages 177 

 and 178. Altitudes of fluids of different densities, inversely as the specific gravities, 

 art. 183, pages 178 and 179. Practical rule for the altitudes, art. 184, page 179. 

 Example for illustrating ditto, art. 185, page 180. A column of mercury of 2 feet 

 and a column of water 33.995 equal to the pressure of the atmosphere, art. 186, page 

 180. The principle of the common or sucking pump dependent on this property, 

 ib. Altitudes in the tubes equal when the specific gravities are equal, art. 187, 

 page 180. Surfaces of small pools near rivers on the same level as the rivers, 

 art. 188, page 180. 



Water may be conveyed from one place to another, of the same or a less eleva- 

 tion, art. 189, page 180. When the source and point of discharge are on the same 

 level the water is quiescent, but when the point of discharge is lower than the 



