2 Forestry Quarterly. 



as oblique an angle as possible, and with the centre of the tree 

 nearest to the source of light. 



In Douglas Fir the writer has obtained in this manner an excel- 

 lent definition of rings as close together as eighteen to five milli- 

 meters, or nearly one hundred to the inch. And records quite 

 good enough for ordinary work may, if necessary, be taken with 

 blotting-paper and a smooth stone. 



With artificial and correctly oblique illumination, graphite, as an 

 aid to definition, may be dispensed with, there being nothing to 

 better the eflfect of the contrast of light and shade upon the white 

 paper. 



If it should be desired to make the records permanent they 

 may be dipped in diluted shellac and dried, when they become 

 as hard as the wood of the original, and from them any number 

 of carbon copies may be taken. The shellac destroys a higher 

 definition than from sixty to seventy rings to the inch, and it is 

 to be supposed that a finer varnish, such as copal or mastic, would 

 be preferable. These the writer has not had an opportunity of 

 trying. 



Thus all the data necessary to enable one to compute the 

 growths of diameter, height, and volume, may be taken from an 

 ordinary tree, (say 24 inches by 100 feet) in lO-foot sections, 

 in fifteen or twenty minutes ; and the curves may be blotted 

 in the ofiice directly from the impressions. 



The records of each tree, or group of trees, may be filed away 

 in an envelope ; and the impressions of the ideal or average tree 

 of his age, height, and diameter, may be made permanent and filed 

 for reference. 



Impressions of full sections may be made, if needful or desir- 

 able, in an ordinary copying press. 



If the method should come into general use, a paper with an in- 

 clastic, and perhaps water-proof backing rolling on to it would 

 seem to be indicated. 



