very just and reasonable, and is evidently based on personal examination. His proposed average of ten annual rings to the inch is almost precisely the same as that obtained by myself (9·7). And his estimate of 300 years as the probable age of a tree with a diameter of 5 ft. at the base, if worked out on the average which my figures have yielded, would only be reduced to 291 years. But, unfortunately, Kirk proceeds to make assumptions respecting the growth of larger trees, for which no sufficient evidence exists, and which are altogether opposed to the information I have been able to obtain. He goes on to say, “The wood of the kauri remains sound long after it has passed its maximum rate of growth; but the newly formed wood cylinders are very thin, while the immense pressure exerted by the outer cylinders consolidates the inner portion of the trunk so that the number of rings to an inch is greatly increased. I have counted over thirty rings to an inch in some gigantic trunks, so that, assuming each ring to represent only a year's growth, the age of a tree 7 ft. in diameter must be 1,260 years. The gigantic specimen at Mercury Bay, which is 80 ft. to the lowest branch and 24 ft. in diameter, must be considerably over 4,000 years; and the fine specimen at Maunganui Bluff, which is 66 ft. in circumference, would not be less than 3,600 years.” Now, the whole of these estimates rest on two assumptions: (1.) That as the tree approaches maturity the newly formed wood cylinders become very thin. This statement is in direct variance with my own measurements of no small number of trees up to 11 ft. in diameter. (2.) That the pressure exerted by the outer cylinders consolidates the inner portion of the trunk so that the number of rings to an inch of radius is greatly increased. But my measurements do not show that the inner rings are “consolidated” in trees of large size; and, in addition, I believe I am correct in stating that authorities in vegetable physiology do not countenance the idea of marked compression of woody tissue in the interior of a trunk due to the successive formation of exterior annual rings. I have already said that the statement made by Kirk to the effect that a tree 5 ft. in diameter would have an average of ten annual rings for each inch of radius, and be 300 years old, must be accepted as a close approximation to the truth. But I fail to see how he can reconcile with it the statement made in the very next paragraph that a tree only 2 ft. wider, or 7 ft. in diameter, would have an age of 1,260 years, with an average of thirty rings for each inch of radius. This is equivalent to saying that during the formation of the additional foot of radius the rate of growth had been diminished to a third of what it previously was. Kirk's contention also implies that the 300 rings which in the 5 ft. tree occupied the radius of 2 ft. 6 in. had been squeezed in the 7 ft. tree into a space of 10 in.! It is unbelievable that the woody layers of a 5 ft. tree could suffer any such compression. But if not, then the 960 annual rings required to make up the full number of 1,260 must be crowded into the extra foot of radius, at the rate of 80 per inch! Not only is such an exceptionally slow rate of growth unknown in the Coniferae, but even no approximation to it has ever been recorded. It is quite clear that Kirk's two estimates are inconsistent one with the other. If the first is accepted, then the second must be swept away. Since Mr. Kirk wrote the “Forest Flora” in 1889 no one has attempted to treat the question in the only accurate manner—that of counting the annual rings of growth in a sufficiently large number of sections of different