GENEEAL PEELIMINAKY PKEPAKATIONS 177 



Another method which would appear to be even more 

 effective, but is more difficult to carry out, is to carry or hang 

 the apparatus on strong steel springs. In this case it would not 

 merely be necessary to let the weight of the whole appliance 

 hang on the springs, but other springs should also be fixed 

 so that they act in opposite directions to prevent the whole 

 apparatus acquiring a periodic oscillation or vibration of its 

 own. It will therefore be essential to connect it by several 

 springs to one support, so that any movement imparted to it 

 is as far as possible stopped at once whatever the direction it 



FIG. 61. Method of supporting Camera to minimise Vibration. 



may take. One method of effecting this is to have a baseboard 

 carrying the whole apparatus on two supporting-legs at each end, 

 both of which are cross-braced to the underside of the baseboard. 

 A strong wooden supporting-frame is then so made that from 

 three separate points at each end, and at each side of the 

 apparatus, springs may be carried to the bottom of the support- 

 ing-legs. These springs require to be strong steel ones, such as 

 may be purchased ready made for a few pence each from any 

 good ironmongery store. It is evidently only possible to 

 indicate in general terms how this arrangement can be carried 

 out, as it must be to a large extent determined by the 

 apparatus and the condition under which it has to be set up. 



