GASEOUS BODIES. 71 



of the mechanical powers that such astonishing effects 

 are produced, as are witnessed in the manufactory of 

 different articles, and which have raised England so 

 much above other nations. At Stroud, in Gloucester- 

 shire, there is a machine which will make 19 millions of 

 pins in a week. Brunei's block machine will make 1420 

 blocks in a day ; and his saw-mill at Chatham, with the 

 assistance of 10 or 12 persons, will perform the labour 

 of 50 saw-pits : it takes the timber from the vessels, and 

 delivers the sawn planks to the stacks. At Weovil, near 

 Portsmouth, eight men and two boys will manufacture in 

 one hour and a half, by means of machinery, ninety hun- 

 dred-weight of biscuits. The advantage obtained in 

 spinning, weaving, &c., are equally wonderful and ef- 

 fective. 



GASEOUS BODIES. 



Nature of Gaseous BodiesComponent parts of Atmospheric Air Oxygen 

 Nitrogen and Carbonic Acid Gas Peculiar properties of each How obtained 

 for experiment, Sec. Component parts of Water Oxygen and Hydrogen 



Properties of Hydrogen, &c. &c. Carburetted Hydrogen Sulphuretted Hy- 

 drogen Phosphuretted Hydrogen Chlorine Nitrous Oxide, or Laughinsr 

 Gas Their properties How obtained for experiment, &c. 



A GASEOUS body is an elastic, transparent, and per- 

 manently aeriform fluid. All gases are said, chemically, 

 to be a compound of solid matter and caloric -, the caloric 

 by its repulsive action separating the particles of the 

 solid, and giving it a gaseous form. The difference be- 

 tween gas, and vapour or steam, consists in the former 

 constantly retaining its aeriform state, while the latter 

 will return to a fluid or solid state when the caloric is 

 abstracted. The affinity between the caloric and the 

 base of the gas is so intense, as to resist any means of 

 separating them, and the gas is consequently rendered 

 perfectly aeriform.* As the kinds of gases are so nu- 

 merous, it is intended here to notice the most important 

 of this class of bodies, of which those that enter into the 



* This is to be understood in a general sense, as many of the gases 

 have been condensed to a liquid state. 



