380 Notices respecting New Books. 



" If one measure of pure oxygen and two measures of hydro- 

 gen be mixed in a jar over mercury, and ignited by the electric 

 spark, both the gasses will disappear, and water will be produced. 

 If two measures of each gas be used, water will be produced a« 

 before, but one measure of oxygen will remain. Hydrogen there- 

 fore unites with v/atcr in one exact proportion, and in no other. 



" If a piece of well burnt charcoal be confined in oxygen gas, 

 and inflamed by a burning glass, the volume of gas is not al- 

 tered when again cooled, but the whole is converted into car- 

 bonic acid gas. If more oxygen be present than is necessary for 

 the consun\ption of the charcoal, the products will be carbonic 

 acid gas and an excess of oxygen ; if there is less oxygen thaa 

 will consume the charcoal, carbonic acid alone will be produced, 

 and part of the charcoal will remain unconsumed. 



" Tlie combination of two elements in several definite propor- 

 tions is very hap])ilv shown by the various compounds of oxygen 

 and azote. These are nitrous oxyd, nitrous gas, and nitrous acid 

 gas. 



*' If two measures of Nitrous Oxyd and two measures of hy- 

 drogen are ignited by the electric spark, the product is water, 

 and two measures of azote remain. Now, as water is produced 

 by two measures of hydrogen and one of oxygen, the nitrous 

 oxyd here employed must have consisted of two measures of 

 azote with one of oxygen condensed into the space of one mea- 

 sure. 



" If charcoal is ignited in two measures of Nitrous gas, the 

 products are one measure of carbonic acid gas and one measure 

 of azote. Hence, as carbonic acid gas always occupies the same 

 volume as the oxygen of which it is formed, nitrous gas consists 

 of equal volumes of oxygen and of azote not condensed by their 

 union. 



*' If two measures of nitrous gas l)e mixed over water with one 

 measure of oxygen gas, both of them totally disappear, and a 

 solution of Nitrous acid gas in water is the result. 



" In all the above examples the proportions of azote and oxy- 

 gen increase or diminish by equal quantities, and no interme- 

 diate states of "combination are known. 



*' Dr. Wollaston has given some striking experiments in illus- 

 tration of this theory of definite proportions in the composition 

 of some super-acid and sub-acid salts*, which may be here men- 

 tioned, as they are easily performed. Let two grains of crystal- 

 lized carbonat of potash, recently prepared, be wrapped in thin 

 pn])er, and passed up into an inverted tube filled with mercury, 

 and let the gas be extricated from it by muriatic acid, and thp 

 apace it occupies be marked on the tube. Then let four grains 



* Phil. Trans, for 1808. 



ef 



