It thus appears that the examination of twenty-nine sections gives 9·7 as the mean number of annual rings for each inch of radius. An average based upon such a large number of examples cannot be very far from the truth, and we may therefore proceed with some degree of confidence to compare it with the estimates given by Kirk in the “Forest Flora.” Let us take first of all the gigantic tree at Mercury Bay, originally reported and measured by Laslett (see “Timber and Timber - trees,” page 389), and subsequently mentioned by Kirk and others. I have already quoted Kirk's opinion that its age “must be considerably over four thousand years.” The exact figures worked out on his own basis of thirty annual rings per inch would be 4,320. But according to my average of 9·7 rings per inch its age would not exceed 1,396 years. And I prefer to take an estimate which, at any rate, is based upon the measurement of a considerable number of examples, in place of accepting one which is little more than a bare assumption. I consider that Kirk's figures are at least three times the proper amount. Similarly, the specimen at Maunganui Bluff, which is 22 ft. in diameter, and which according to Kirk has an age of 3,960 years, under my views would not exceed 1,280 years. Kirk's assertion that “the age of a tree 7 ft. in diameter must be 1,260 years” I have already combated on the ground that such an estimate is altogether inconsistent with his very reasonable and correct view that a 5 ft. tree would be 300 years old. Worked out on my average of 9·7, the age of the 7 ft. tree would be 407 years, and that of the 5 ft. tree 291 years. The great majority of the kauri-trees that are now cut for sawing range from 3 ft. to 8 ft., and the age of such trees, according to my calculations, and subject only to a very narrow limit of error, would be 174 years for the 3 ft. tree and 465 years for the 8 ft. one. It may be objected that some weight ought to be attached to Kirk's view that in trees of large size the increment of woody tissue formed each year would progressively decline. But as long as the environment of the tree is suitable, and the production of foliage is maintained, there is no reason why that should take place. It is well known that a tree does not cease growing when it arrives at maturity. Professor Marshall Ward says that “as long as it is alive it continues to increase in bulk by the addition of the annual layers developed by the cambium; but when maturity is once passed each succeeding year produces a certain amount of deterioration at the centre.” This deterioration ultimately leads to the tree becoming hollow, but that does not prevent the cambium from forming additional layers. Strasburger says (“Text-book of Botany,” p. 239), “All that is actually visible of a thousand-year-old oak is at most but a few years old. The older parts are dead, and are either concealed within the tree, as the pith and wood, or have been discarded like the primary cortex. The cells of the original growing-point have alone remained the whole time alive. They continue their growth and cell-division as long as the tree exists.” It is almost needless to say that in most parts of the world numerous examples have been cited of hollow trees which are known to have continued their growth for long periods. With respect to the kauri, in trees of large size it is quite common to find the lower part of the trunk hollow. While engaged in measuring the sections just tabulated I noticed several instances the exact age of which I was unable to determine on account of decaying wood or cavities in the centre. All these trunks had well-developed rings of growth near the circumference. One in particular, which measured