J. F. Martley 231 



amined, and, to ensure correspondence in numbering along the different 

 radii, the rings were followed completely round the disc. In places where 

 the rings were indistinct, only the more prominent were traced round 

 while the space between two such prominent rings was divided into a 

 convenient number of equal subdivisions. 



Where the growth of the tree did not show any great irregularities 

 there would be little error in the contemporaneity of these "pseudo- 

 growth rings" along the different radii of the disc. 



After the rings had been counted and numbered, a number of sticks, 

 usually eight in all and at an angle of 45 degrees to each other, were 

 sawn radially out of the discs, care being taken to make the sides of the 

 sticks as near as possible perpendicular to the surface of the disc. The 

 sticks sawn from the disc constituted the transverse series for that 

 species. 



The longitudinal series were prepared by sawing a radial board of 

 each species transversely into a number of sticks an inch in depth. The 

 rings were counted on the corresponding transverse surfaces, differences 

 of width and of tint ensuring correspondence in the numbering of the 

 rings in the sticks of each longitudinal series. 



Subsequent to the measuring of the width of the rings, the sticks of 

 each transverse and longitudinal series were submitted to the following 

 treatment. 



By using a knife each stick was divided up into a number of thin 

 slips by splitting parallel to the rings. So far as the width of the rings 

 permitted a, division was obtained between each ring, and in the broader 

 rings as many as three or four splits were easily made. In order to 

 prevent confusion the number of the ring was marked on each slip, a 

 precaution necessitated by the large number of slips obtained from each 

 stick. 



The inclination of the grain was then measured on the outer tan- 

 gential face of the slips and tabulated in conjunction with the width of 

 the rings for each stick. 



Lettering the outer face of a slip as in Fig. 2 the grain was traced 

 by means of a lens and a fine needle from the top corner (B) or bottom 

 corner (C) of the right-hand side BC, according to whether the inclination 

 of the grain was right-handed or left-handed, to where it met the opposite 

 side, CD or AB as the case might be, at the point X. By measuring XC 

 or XB and the side BC with a micrometer screw, the angle of inclination 

 of the grain (6) to the straight could readily be calculated from the 

 tangent. 



