PRESERVATION OF TIMBER. 355 



oil usually specified is about 8 to 10 Ibs. per cubic foot, while 

 for marine purposes 10 to 12 Ibs. per cubic foot has hitherto been 

 considered sufficient. 1 For the higher temperatures of sea water 

 on the French coast and in the southern harbours of the United 

 States, a charge of about 19 Ibs. per cubic foot is required to 

 insure immunity from the attacks of the worms. 2 In dealing 

 with New Zealand woods, Mr. W. Sharp found that the quantity 

 of sap produced by white pine was practically T08 gallons per 

 cubic foot; by Eimu 0'97 gallon per cubic foot, and by Miro 

 0*705 gallon per cubic foot; and that the correct quantity of 

 creosote for each of these timbers, allowing for a slight excess 

 over sap extracted, was for white pine 13*8 Ibs. per cubic foot, 

 for Rimu 12*4 Ibs. per cubic foot, and for Miro 9 Ibs. per cubic 

 foot. 8 



The charges placed in the cylinder should consist as nearly 

 as possible of timber of the same class, length, scantling, density, 

 and degree of dryness, otherwise the quantity of creosote absorbed 

 by the several pieces making up each charge will be irregular, 

 and the result unsatisfactory. 



All timbers should be converted and all bolt-holes bored 

 before treatment, otherwise any work upon them penetrating to 

 parts not so thoroughly saturated with creosote as the outsides 

 may form inlets for decay and points of attack by the worm. 



A system introduced by Mr. H. Aitkin, of Falkirk, consists 

 simply of soaking the timber in melted naphthaline, for a period 

 of from two to twelve hours, depending on the bulk of the piece. 

 A temperature of 180 to 200 Fahr. is all that is required for 

 the process, and is most easily obtained by placing steam-pipes 

 in the bottom of the tank containing the material. A valuable 

 feature in this process appears to be that it can be applied to 

 green timber. The naphthaline makes its way through the pores 

 of the wood, decomposing the albumoid compounds and dis- 

 placing both sap and water. The naphthaline then becomes 

 fixed, and the whole substance is permeated with a solid anti- 

 septic substance of a permanent character. A further advantage 

 attributed to this process is, that it does not render the timber 

 more difficult to cut; neither does it interfere with its being 

 worked, painted, or varnished. 4 



Hayford's system of creosoting, introduced in America some 



1 M.P.I.C.E., vol. Ixxxiii. p. 448. 2 Ibid. Ibid., xciii. p. 414. 



* Engineering, vol. 1. p. 607. 



