520 



Simple and expeditious Modes 



piece like a shoemaker's measuring rule. An ingenious instru- 

 ment of this sort has been invented by Mr. Blackadder of 

 Glammis, in Forfarshire ; and it has been in use by him many 

 years. He has kindly promised us a paper on the subject of 

 measuring trees, with a view to the ascertaining of the quantity 

 of the timber they contain ; with which, knowing Mr. Black- 

 adder's ingenuity, general knowledge, and extensive experience, 

 we are sure our readers will be much gratified. 



Since the foregoing article was sent to press, we have received 

 the following communication on the subject from our ingenious 

 friend Richard Varden, Esq., well known to the readers of our 

 EncyclopcEdia of Architecture and Architectural Magazine^ and now 

 established as an architect and landscape-gardener in the city of 

 Worcester. 



" There is a small instrument, which I have employed for as- 

 certaining the heights of trees, that I think might be useful to 

 the contributors to your Arboretum Britannicum^ as it would 

 enable them to fill up the third column of your Return Paper 

 with greater ease than by measuring with rods. This instrument 

 is a modification of a quadrant or sextant, and it is graduated 



on a principle which I shall presently explain. It is made of a 

 piece of thin board of the form shown inj^. 91., graduated in 

 feet on the lower edge, or circumference, and with a line and 



