FIRST RESEARCHES IN PHYSICS 55 



like those of light. For the polariser and analyser of the 

 optician, he employed grids of metal, each a row of parallel 

 wires, and found that electric vibrations parallel to these 

 were absorbed, while those at right angles to the wires could 

 pass through. When the two gratings were parallel, the 

 electric beam passed through ; but when placed at right 

 angles to each other, it was completely stopped, just as for 

 light with the crossing of Nicol's prisms. Broadly then, 

 Hertz's comparison of the new electric rays with light was 

 so far complete, and the confirmation of Maxwell's theory 

 accordingly. 



There remained of course much to be done : both as 

 regards the improvement of the whole range of apparatus 

 in detail, and the increased precision of research towards 

 bringing in other considerations which hold good in 

 the case of light, not to speak of unknown developments. 

 There can be no doubt that Hertz would have gone further 

 in such directions ; but at this stage his weak health 

 doubtless overstrained by those years of intense thought 

 and labour, aggravated more or less by neglect gave way ; 

 and he died of an ailment even then rarely fatal, and now 

 easily treated by the surgeon the consequence of a mere 

 nasal catarrh. The regret throughout the scientific world 

 for this early loss has rarely been paralleled the only fully 

 analogous case within the writer's memory being that of 

 Francis Balfour, the embryologist of Cambridge, in an 

 Alpine accident now some thirty-five years ago. But, as 

 Hertz had wished, the path was opened ; and able physicists 

 entered on it, first to test and verify, then to extend the 

 investigation in new directions. The first defect to be 

 grappled with was the uncertain behaviour and irregularity 

 of discharge of the balls between which the oscillating dis- 

 charge took place. Hence to improve this portion of the 

 apparatus to ensure ' good ' sparks without ' bad,' has been a 

 main endeavour for subsequent investigators. Here Lodge 

 and Bose were specially successful : the first by intro- 

 ducing an intermediate ball, which served as a regulator of 



