258 Double Cross-Grain 



simultaneous; and the rate of change in inclination of the grain is not 

 the same at different transverse levels in the same radial plane at the 

 same moment resulting in the prominence of a period varying through the 

 series. 



In estimating the average period lengths and amplitudes in the 

 longitudinal series, it was only possible to arrive at approximate values. 

 The figures that were obtained showed that the period length and 

 amplitude had their maximum value near the exterior but no gradual 

 increase in value with age was shown as in Shorea robusta. 



The disturbance caused by a small branch trace is shown very clearly 

 in sticks 15, 16 and 17 of the longitudinal series. The branch trace passed 

 horizontally outwards at the side of stick 16. The curves of sticks 15 

 and 17 show that as in straight-grained wood the grain as a whole curves 

 round the knot retaining, however, its cross-grained character. 



XYLIA DOLABRIFORMIS. 



As the disc had already been used for a general investigation of the 

 course of the grain, it was only possible to examine the course of the 

 grain in detail in the plane of a radial board. 



The data for the sticks of the longitudinal series are not printed here 

 but the curves constructed from them are given in Fig. 8. 



Taking the results obtained from the investigation of the disc in 

 conjunction with the longitudinal series, it is clear that, as in the other 

 species examined, the inclination of the grain as a whole alternates with 

 growth between right-handed and left-handed, and also, as in the other 

 species, the absence of complete contemporaneity of the periods at the 

 various transverse levels and differences in the rate of change in the 

 inclination of the grain at any moment, result in the grain consisting of 

 a series of superposed serpentine curves. 



HARDWICKIA BIN AT A. 



In the transverse series the rings were counted accurately only as 

 far as the 27th ring, after which only the more prominent rings lettered 

 V, W, X and Y were traced round. In each stick the space between each 

 two of these prominent rings was divided up into eight pseudo-growth 

 rings of equal width. This procedure was adopted as the disc had not 

 been smoothed sufficiently for tracing the fainter rings. 



In the longitudinal series on the other hand the rings could be counted 

 with precision from the centre to the exterior. As the board did not 

 contain the pith the numbering of the rings in the two series does not 



