SH 



BALANCE LEVEL. 



If you think proper, an insertion of this explanation in 

 your valuable Journal will greatly oblige, 

 Sir, 



Your most obedient Servant, 

 Old Broad Street, JOHN MARTIN» 



19 Juli/, 1808. 



VI. 



Xfescription of a Balance Level, useful for lading out Land 

 for Irrigation, for Roads, and other Purposes. Bif Mr, 

 Richard Dhew, of Great Ormond Street *. 



SIR, 



He] 



]REWITH you will receive a Balance Level, of my 

 invention, whichi have satisfactorily used on several gentle- 

 men's estates in Devonshire, where I have been employed 

 to drain and carry water to irrigate meadow land. I have 

 made several for persons in that county, whose employment 

 is to drain and irrigate land, and they have found \t to an- 

 swer their purpose better than the spirit or water level, it 

 being more portable and ready to the sight. 



I have lately used it on Mr. Satterley's farm, at Hastings, 

 to carry the water of his closes over several acres of dry 

 ground. Dr. De Salis, who has seen it, advised me to send 

 it to the Society of Arts, &c., that they might judge of its 

 ii\erits. 



I am, Sir, 



Your obedient Servant, 



RICHARD DREW. 



Explanation of the Method of using the Instrument. 

 Method of Set it on a triangular staff, and point it at the object staff, 



using It. which is held by another person at a distance; move the 



level on the joint, until the inner tube plays clear within 



* Trans, of the Society of Arts for 1807, p. 22, The Society 

 voted Mr. Drew ten guineas for this invention, 



the 



