56 On the Cause of Chemical Proportions. [Jan. 



oxygen ; and the 2 volumes of ammouiacal gas contain half as 

 much oxygen in weight as the quantity of silica which exists in a 

 volume of silicated fluoric acid. Hence fluoric acid must contain 

 likewise twice as much oxygen as ammonia. Hence it follows that, 

 removing the silica, the fluate of ammonia remaining is composed 

 in such a manner tiiat the acid contains twice as much oxygen as 

 the base. 



When we compare the analysis of the gaseous silicated fluoric 

 acid with that of the sul)fluate of ammonia formed when we sepa- 

 rate the silica from the fluate of ammonia-and-silica, we find that 

 the ammonia which comes in place of the silica contains li times 

 as much oxygen as the silica;* and consequently in the subfluate 

 of ammonia the base contains twice as much oxygen as the acid; 

 that is to say, that the acid is combined with four times as much 

 ammonia as in the triple salt. 1 request the reader who wishes to 

 follow these calculations to compnre what I have said here with the 

 interesting memoir of Mr. John Davy in the Philosophical Transac- 

 tions for 1812, and likewise with what I say in the sequel when 

 speaking of silica. 



As there is such a correspondence in the experiments of Mr. 

 John Davy, 1 consider it as most probable that fluoric acid contains 

 nearly 77 P'"ts of oxygen and 26 parts of radicle, and that these 

 77 parts are 2 volumes. Hence the volume of fluoric radicle ought 

 to weigh almost exactly as 60. If the analysis of fluate of lime by 

 Dr. Thomson were most exact, the radicle would weigh as high 

 as 80. 



5. Boraciaim, horon (B). — We know, from the ingenious experi- 

 ments of Sir Humphry Davy, as well as from those of Thenard 

 and Gay-Lussac, the nature of this body in a separate state. Davy 

 found boracic acid to contain 73 per cent, of oxygen, while Thenard 

 and Gay-Lussac affirm that it contains only the third of its weight 

 of that principle. To determine the composition of this acid, 1 

 have examined some of its combinations, in order to ascertain its 

 capacity for saturation. 



1. Boracic add and u- at er. — {a.) A portion of vitrious and very 

 pure boracic acid wasdissolved in boiling water, and th.en crystallized. 

 The crystals were dried, reduced to powder, and exposed upon paper 

 for 24 hours to the temperature of 68°. The acid thus dried was 



* Silira is supposed to be com-po^ed of 48 oxy2:en and 52 siliciim. The fluate 

 of ammonia-and-S'ilica is composed 'n such a manner thaf the 07tv;;eii of the am- 

 monia being 1, lliat of the .-ilioa .Trd of the fliiorir acid is each ?. Now if (he 

 ammonia replartd ihe lilira in such .i miinorras to contain a quantity of oxygen 

 equal to that in the silica diseng.ijrd, the oxyicn of the whole ammoni.i oui^lit to 

 be equal to ihe oxygen of the silica and to the oxygen of the ammonia in the 

 triple salt; that is to say, tha: tliejoxy^'-'ii in the base ought to be to that in the 

 acid as 3 : 2. FSut as this is contrary to the laws of c'.erniia! proportions, it is 

 necessary that tlie ammonia which taUes the place of the silica should contain 

 either i the ox>;ceri in the silica, or li the oxygen; that is to say, that in Ihe 

 neutral fluate of ammoiii.i the ammonia ou^ht to contain a quantity of oxygen 

 • qunl tu that in the arid, or twici as much. 



