24 r>. p. PENHALLOW ON 



PiNTJS ALBICAULIS. 



(Plate I., fig. 5.) 



Seasoned in the log for three months this specimen developed a number of star shakes, 

 with a few irregularly tangential connecting fractures. These were in all cases determined 

 primarily along the medullary rays. The additional influence of furnace heat caused no 

 alteration in' the number of fractures, although it caused those already established to open 

 much wider, and the whole specimen to contract more strongly in volume, a change which 

 has continued to the present time. The shakes established wei'e not more numerous than is 

 commonlj' met with in timber seasoned under similar conditions. 



Under the hatchet or chisel the wood splits with facility, but the line of fracture, as in 

 Plnus ponderosa, conforms strictly to the position of the instrument, and otherwise follows 

 the rays in the first instance as the lines of least resistance. 



The section removed from the log, after three months of seasoning and submitted to a 

 more powerful desiccation, showed no farther alteration, indicating again, as in the previous 

 cases, that the pronounced development of shakes is consequent upon seasoning in the log. 



Section a, submitted to maceration for one month and desiccation for two and one-half 

 months, also section b, macerated for four and one-half months, followed by desiccation, 

 showed no alteration whatever, although the maceration was attended by a copious fungoid 

 growth and their mycelia penetrated the structure freely. The growth-rings are uniformly 

 broad, with a width of 2-5 to 4 mm., and prominent. Tlie thin summer wood is incon- 

 spicuous. 



Although the resin is not copious, its exudation from the sap wood was much stronger 

 than in any of the other species examined. Microscopical sections show the resin-passages 

 to be scattering and in no sense collected in bands or plates. They have an average diameter 

 of 0-105 mm. and number twenty-six per square centimetre. 



In a specimen of this wood from the Sargent collection the resin-passages are aLso scat- 

 tering, 0-096 mm. broad and sixty-two per square centimetre. Here again, as in Pinns 

 ponderosa, while the resin-passages of the Kootanie specimen are slightly larger, they are 

 less than half as numerous, so that the variation affords strong evidence in opposition to the 

 view that the resin can have any relation to the breaking up of the structure. 



The evidence thus obtained may now be examined in its special bearing upon («) the 

 original statement that in certain woods of the Kootanie valley the resin occurs in plates in 

 such a way as to cause the timber to fall apart in seasoning; and {b) upon the character and 

 origin of the Kootanie coals. 



((/) Our examination of the four woods from the Kootanie valley shows that in each 

 and every case, Avith one exception, there is absolutely no tendency towards the aggregation 

 of the resin in plates or bands, but that, on the contrary, the resin-passages are scattering, 

 small and never numerous, while in more than one instance they are less, both in number 

 and size, than in woods of the same species from other localities, and less than the average. 

 It thus appeai-s that in this respect there is absolutely no foundation for the representation 

 made, and yet that representation was evidently based upon some structural feature of the 

 wood, the true nature of which was not understood, and was therefore subject to misinter- 

 pretation. 



