BORACIC ACID 



The boracic hcid of tho Tuscan lagoons is,'obtained from nine different works : 

 Passo, Larderollo, Lervazano, Monto Cerboli, Castel Nuovo, Monte Kotondo, San 

 rrederigo, Lustignano, Lago ; producing 163,855 avoirdupois pounds per month. 



The late Count Larderol furnished Mr. W. P. Jervis with tho following statement 

 of tho production of boracic acid, from the commencement of the works to tho year 

 .1859: 



Tons Cwts. Tons Cwts. 



From 1818 to 1828 521 16 1849 1,043 13 



1829 1838 4,870 6 1850 1,043 13 



1839 748 13 1851 1,140 



1840 878 13 1852 1,156 19 



1841 886 6 1853 1,208 19 



1842 923 15 1854 1,319 7 



1843 923 16 1855 1,332 19 



1844 923 16 1856 1,427 1 



1845 923 15 1857 1,711 4 



1846 1,043 13 1858 2,026 10 



1847 1,043 13 1859 1,803 18 



1848 1,043 13 



Society of Arts' Journal. 



Although the boracic acid in the lagoons of Tuscany was discovered in 1777 by 

 Peter Hoeffer, apothecary to the Grand-Duke of Tuscany, until 1818 all the efforts 

 made to render it profitable to obtain it were of the most desultory character, and 

 generally failures. In 1818 Count Larderel established the first works at Monto 

 Cerboli, and used artificial heat to effect the evaporation. In 1828 ho began to use 

 the natural heat of the soffioni to evaporate the boracic waters of the lagoons, effecting 

 thus an enormous saving and greatly extending the works. 



The late Professor Graham, in his ' Report on the Chemical Products of tho Great 

 Exhibition of 1851,' thus speaks of Larderel's discovery : 



' The preparation of boracic acid by Count F. do Larderel, of Tuscany, was re- 

 warded by a Council medal. Although this well-known manufacture is not recent, 

 having attained its full development at least ten years, still the bold originality of its 

 first conception, tho perseverance and extraordinary resources displayed in the suc- 

 cessful establishment, and tho value of the product which it supplies, will always place 

 the operations of Count de Larderel among the highest achievements of the useful arts, 

 and demand the most honourable mention at this epoch. The vapour issuing from 

 a volcanic soil is condensed, and tho minute proportion of boracic acid which it con- 

 tains (not exceeding 0'3 per cent.) is recovered by evaporation, in a district without 

 fuel, by the application of volcanic vapour itself as a source of heat. The boracic 

 acid thus obtained greatly exceeds in quantity the old and limited supply of borax 

 from the upper districts of India, and has greatly extended the use of that salt in the 

 glazes of porcelain, and recently in the making of the most brilliant crystal, when 

 combined with the oxide of zinc instead of the oxide of lead.' Reports of the Jurors of 

 the Great Exhibition of 1851. 



Various hypotheses have been advanced to explain the origin of the boracic acid 

 in the heated vapours of the Tuscan lagoons. Boracic acid is not known in an im- 

 combined state as a constituent of any rock, but it seems likely that the deep-seated 

 rocks whence the A-apours issue may contain certain borates such as boracite and 

 by the action of hot aqueous vapour on these compounds boracic acid may be elimi- 

 nated. 



Tho processes of chemical alteration taking place beneath the crater of Vulcano, 

 already spoken of, may, according to the statement of Hoffmann, depend upon con- 

 ditions very similar to those existing in Tuscany. There, likewise, sulphuretted 

 hydrogen is associated with the boracic acid, and, it would appear in much greater 

 quantity, since the fissures through which the vapour issues are thickly lined with 

 sulphur, which is in sufficient quantity to be collected for sale. A profitable factory 

 is established at the place, which yields daily, besides boracic acid and chloride of 

 ammonium, about 1,700 Ibs. of refined sulphur and about 600 Ibs. of pure alum. 

 Bischof. 



The boracic acid obtained from the waters of the Tuscan lagoons by tho process 

 previously described is always more or less impure. M. Payen has given the fol- 

 lowing as the composition of this crude boracic acid for 100 kilogrammes : 



Pure crystallised boracic acid . . . 74 to 84 



Sulphate of ammonia, magnesia, and lime . . 14 to 8 



: Sand and sulphur 2'5 to 1*25 



Hygroscopic water disengaged at 35 C. . , 7 to 575 



Azotic matter, hydrochlorate of ammonia, &c, , 2'5 to 1 



