V. MASS. 89 



D. INSTRUMENTS FOR DETERMINING SPECIFIC GRAVITY. 



347. Tangential Balance for measuring the density of 

 liquids and solids by the angle of inclination, read on a divided 

 circle to two minutes, thus giving the third decimal of specific 

 gravity ; made by Oertling, of London. 



Prof. Carl Wenzel Zenger, Prayue. 



355. Hydrostatic Balance, by Ramsden; with Weights, 

 by Robinson, presented to the Royal Society by Lady Banks. 



Royal Society. 



368. Xylometer (cylindrical form), with brass cylinder. 



Zimmer Brothers, Stuttgart. 



369. Xylometer of Glass, prismatic form. 



Zimmer Brothers, Stuttgart. 



These instruments are chiefly used in the management of forests, and for 

 agricultural purposes. 



They are employed for exact scientific examinations, especially for the 

 cubing of irregularly-shaped pieces of wood, and for determining the specific 

 gravity of wood. 



Discs of wood which have been split out from the heart in the direction of 

 the pith rays, and therefore contain proportionate parts of all veins of wood, 

 can be quickly and exactly examined. 



With both apparatus it is possible to read on the scale accurately down to 

 5 cub. centimeter (5 grammes water). 



(See " Holzmessekunst," by Prof. Dr. Baur, Hohenheim.) 



425. Hydrostatic Apparatus for ascertaining the specific 

 gravity of woods. 



Prof. Dr. Nordlinger, Hohenheim, Wurttemberg. 



372. Densimeter of Major Bode's construction, for determin- 

 ing the specific gravity of all sorts of powder. 



A. and R. Hahn, Cassel. 



The densimeter is the only existing instrument with which the specific 

 weight of all sorts of gunpowder (prismatic powder, powder-cakes, fine and 

 coarse grained powder, &c,), can be easily determined, in quantities of 50 to 

 250 grammes, with the most perfect accuracy. 



It is constructed by Major Bode. 



This apparatus consists of a reservoir with bolt, two gutta-percha tubes, and 

 a clamp. 



1 . The reservoir is formed by a steel capsule, with lid fitting air tight. 



By means of the bolt the lid of the steel capsule can be screwed fast on 

 this. 



The contents of the reservoir are so measured in the clear that a prismatic 

 powder grain can be easily placed in it. 



Lid and steel capsule are vaulted, in order to accelerate the exhaustion of 

 the air by pumping. 



In the steel capsule in the upper part and in the lid in the lower 

 part, there is an air-tight cock. The reservoir communicates with these 



