610 



PROCEEDINGS OF SECTION I. 



VII.^INSTRUMENTS. 



The full equipment of instruments required for the measurements 

 acheduled is — 



1. Weighing machine. 



2. Height meter. 



3. Callipers. 



4. Tape. 



5. Spirometer. 



The approximate prices are given below. 



WEIGHING MACHINES. 

 There are two main types — (A) spring balance. (B) steelyard. 



(A) Spring Balance Weighing 

 Machine. 



The spring balance (Fig. 1) 

 may be suspended from a stout 

 frame or a doorway, and from 

 it hangs, by light chains or 

 ropes, a seat as in a child's 

 swing. 



This type is suitable for 

 schools where ease and rapidity 

 of weighing are important con- 

 siderations. It is, however, 

 liable to be deranged by shocks, 

 and should therefore be frequently 

 tested. 



(B) Steelyard Weighing 

 Machines. 



In the most convenient form 

 of steelyard weighing machine 

 the steelyard is supported on 

 p^fj 1 the top of a pillar on a level with 



the eyes of the observer. The 

 platform, on which the person to be weighed stands, is supported 

 by knife-edges on levers housed in the base of the machine, and 

 ©onnccted by a rod passing up the centre of the pillar to the short 

 end of the steelyard. 



