84l Mr. Gilbert Burnett on the Decay 



and by what weight each bends and breaks : the probable 

 durability should be tested by taking equal portions of each 

 rod, and steeping them for equal periods, both in hot and in 

 cold water, then drying them and steeping them again for eight 

 or ten times, once a day, and the quantity of extract contained 

 in the respective waters will be a tolerable criterion of the rela- 

 tive solubility of ligneous material possessed by each. 



Dutch wainscot, American clap-board, French and Norway 

 oak tinge the water deeply, and all part with a consider- 

 able proportion of their substance ; good English oak yields 

 comparatively little. Of English oak, the pedunculata parts 

 with much less of its substance, and much less speedily, than 

 does the sessiliflora, and that less than the pubescens; yet 

 specimens of young and immature timber of the naval oak I 

 have found to be little better than the inferior foreign plank. 



I purposely avoid indulging, at the present stage of the in- 

 quiry, in any prolix details of the various experiments, to a 

 statement of the general results of which I have endeavoured to 

 confine myself: however, to take a few examples, I find, from 

 notes made by Mr. Waterworth, who assisted in the manipu- 

 lations, the average solubility of the ligneous material, in six 

 specimens of oak submitted to experiment, to have been as 

 follows : — 1* ; 2- ; 25 ; 3- ; 4* ; 5* 5 to 5*25 ; i. e. when equal 

 weights, say 450 parts, of mature, well- seasoned British naval 

 oak ; of the same, ill-seasoned ; of the same, immature ; of pu- 

 bescent oak, of choice Norway oak, and of right Dutch wain- 

 scot, were steeped in equal quantities of water, say 1800 parts, 

 at the same temperatures, and for the same periods, the rela- 

 tive losses, as ascertained by the increased densities of the 

 several infusions, and the weight of the extracts obtained by 

 evaporating equal quantities of each, averaged, of the Nor- 

 way, double that of the good British naval oak ; of the Dutch, 

 four times as much ; and of the pubescent, five to six times 

 as great : the loss of the immature and ill-seasoned British 

 naval oaks, as compared with mature and well-seasoned spe- 

 cimens, averaged two and a half and three times as much : 

 therefore, if the loss of the good naval oak be taken, as 1*, that 

 of the Norway will be 2* ; of the ill-seasoned, 2*5 ; the imma- 

 ture, 3- ; the Dutch 4* ; and the immature pubescent, 5* to 5-25, 



Subsequently to repeated infusions in water of different tem- 

 peratures, the specimens still wet should be put out of doors 



