n^, METHOD OF VALUING GROWING TIMBER. 



finitely small and equal de^jfrees, the corresponding incre- 

 ments of evaporation are proportionals to the evaporation 

 itself; a singular property, and which, it seems to me, may- 

 lead to a more accurate knowledge of the nature of evapo- 

 ration, and decide between the two celebrated systems of 

 Leroy and Dalton, which at present divide the suffrages of 

 natural philosophers. 



III. 



Method of ascet'taining the Value of Growing Timber Trees 

 at different and distant Periods of Time : Bij Mr. Charles 

 Waist ELL, of High Holborn*. 



SIR, 



Methodof as. CyONCEIVING, that the Tables contained in the an- 

 ccriaining the nexed papers will affm-d useful information to growers of 

 ing'tlmbe^r!"*' timber, and tend to encourage the growth of it in these 

 kingdoms, and hereby promote the views of the Society of 

 Arts &c., I trust you will have the goodness to lay them 

 before the Society, as I have formed them with great at- 

 tention. 



Having last autumn viewed some plantations made under 

 my direction about thirty years ago, I found the value of one 

 of them much to exceed my expectation. 1 became there- 

 fore desirous to devise some means of estimating what its 

 value might probably be at different future periods. I was 

 thus led to construct the first of these tables, and on the 

 completion of this, other tables seemed necessary, and I was 

 thus progressively led on to the construction of the whole. 

 For this purpose I searched in various authors for the mea- 

 sure of trees, in girVh and height, at different ages, and pb- 

 General in- tained similar infornriation among my acquaintance. Hence 



crejseul iroes j (.oH^.f-ted, that t>.e increase in the circumference of trees 



in height aiia 



girth is generally from about one to two inches anjiually, and 



* Trans, of ihe Soc. of Arts, vol. XXVI, p, 45. The j^old medal of 

 the Seciety was voted to Mr. W'aisiell for this comnjunicatiou. 



fron? 



