82 KANSAS CITY REVIEW OF SCIENCE. 
to burn. The third process, and the one which has been the most thoroughly- 
tested, is that of M. de Lapparent, as used in the dockyards of Cherbourg, Dant- 
zic, and Pola. 2 A jet of flame from a specially constructed coal-oil lamp is 
thrown upon the surface of the wood to be preserved. The outer layer is car- 
bonized, while the layers immediately beneath undergo a partial destructive dis- 
tillation which results in the formation of antiseptic, empyreumatic substances 
within the wood. This method has been highly recommended for the preserva- 
tion of ship timbers, but is manifestly inapplicable to cases in which numerous 
small pieces are to be handled, as with wooden pavements. The cost of the 
labor involved in carbonizing the immense surface of the necessarily small blocks 
would be unbearable. There is an improvement upon de Lapparent' s process, 
due to Hugon.3 The difference is in the construction of the lamp. The im- 
proved method has been successfully employed in France for the preservation of 
telegraph posts. 
In the third class of processes we find all those whereby the wood may be 
charged with insoluble mineral substances, and so protected from change. These 
all depend upon the principle of double decompositions — the wood being succes- 
sively impregnated with two solutions which are capable of precipitating each 
other. Methods of this sort were proposed by Gossierin 1828; Treffry, in 1838; 
and Fliselli, in 1840. In 1837, the Industrial Society of Annaberg recommended 
the use of water-glass and hydrochloric acid. Ransome seems to have reiterated 
this suggestion, possibly with modifications, in 1845. Burkes, in 1844, proposed 
water-glass and sulphate of iron ; and Feuchtwanger has recommended soluble 
glass and lime-water. In 1846, Venzat and Banger suggested the use of sulphate 
of copper with caustic baryta, Muller* claims to have obtained good results 
with sodium phosphate and barium chloride; and Schweitzer ^ asserts that a com- 
bination of sodium sulphate and calcium chloride has merits. But Payne's proc- 
ess, brought forward in 1841, has been more thoroughly tested than any other 
in this class. Payne tried experiments with various saline couples, but especially 
with a mixture of the sulphide of barium or calcium, with the sulphate of iron. 
Sulphide of iron and the sulphate of the earth were of course formed within the 
wood. The process, however, was costly and imperfect, and is now pretty much, 
if not altogether, abandoned. The same may be said of similar double processes. 
I have cited these methods only for the sake of completeness. 
All the preservative processes at present in vogue belong to our fourth and 
last class. They depend upon the injection of various antiseptics into the wood, 
and vary not only with regard to the antiseptic used, but also in the method of 
applying it. The^ simplest method of application is merely to soak the wood in 
the preservative liquid. Almost as simple is the device of boiling the wood in 
the antiseptic. At one time, Boucherie recommended absorption by the living 
tree. Deep cuts were made in the trunk near the roots, a sort of tank built 
2 Dingier 's Pol, Journal, 181, 42, 1866. 
3 Dingl. Pol. Jour. 189, 456, 1868. 
4 kci. Amer. 25. 328, 1871. Dingl. Pol. Jour. 202, 290, 1871. 
5 Dingl. Pol. Jour. 125, 121, 1852. 
