I3S 



Transverse Tests — CaUitris glauca: 





No. I. 



No. 2. 



No. 3. 



Size of specimen in inches 







B. 



3-02, D. j-03 



B. 



2-968, D, 3-025 



B. 3-005, D. 3-02 



Area of cross section, sq. inches 









0-15 





8-qi8 



9- Ob 



Breaking load in lb. per sq. inch 





... 





4.S50 





4,200 



3,050 



Modulus of rupture in lb. per sq. 



m 







0.448 





8,520 



6,010 



Modulus of elasticity in lb. per 



iq. 



in. 





1,010,470 





1,133,160 



875,675 



Rate of load in lb. per minute 





... 





485 





451 



210 



Three smaller pieces, 12 in. by i in. by i in. gave the following results: — 

 deflection -37 in.; ^2; broke at 850 lb., deflection -28 in. ; (3) 

 broke at 6go lb., deflection -20 ni. 



i^i broke at 900 lb 



(b) Anatomy. 



Very little if anything appears to have been done to investigate the 

 anatomical structure of the timber of Australian CaUitris, or at any rate our 

 researches through the Conifer literature at our disposal revealed little or nothing. 

 The data now given should, therefore, prove of interest in the future study of 

 this genus. Phylogenetically the results are of some value, for a connecting link, 

 so to speak, was found to exist between these living CaUitris and the fossil pine 

 woods of Australia and North America, in that some of the tracheids of the 

 xylem contain a similar dark substance — its chemical identification being touched 

 upon in another part of this work. 



A transverse section of the timber viewed under a low magnification as in 

 Figure 79, shows a more or less irregularity in the diameter and thickness of the 

 tracheidal walls between the several medullary rays. This figure is interesting, in 

 that there is quite an absence in the picture of any manganese compound in any of 

 the tracheids ; this is an unusual occurrence, and it simply shows that it is possible 

 to obtain portions without this compound in the cells. The line of smaller or 

 closely packed cells marks the autunmal growth and the point of transition from 

 that season's wood structure to that of spring. 



Under a higher magnification, as in Figures 80 and 81, a rather 

 more uniform size of cell obtains, for althougli the tracheids are of varying 

 diameters, yet the walls may be said to be of a fairly uniform thickness; in 

 Figure 80 the black lines running from top to bottom arc the parenchymatous cells 

 of the medullary rays filled with manganese compound — the " end-on-view " of 

 w^hich is shown in Figures 84 and 85. In 80 and 81 are more j^lainly seen the 

 autumnal tracheids with tln-ir restricted growth, and wliicli lonn a darker line 

 across the lower portion of the plate, Figure 80; these cells are sliglitly enlarged 

 in Figure 81. The gradual diminution in size of the tracheids during this period 

 is well seen, as also is the sudden change to enlarged tracheids of the spring period. 



