144 LIFE AND WORK OF SIR JAGADIS C. ROSE 



any required period of oscillation in practice usually from 

 once in a second to once in a quarter of an hour, as may be 

 required while the oscillations and their dotted records 

 can go on as long as the winding of the clock is attended to. 

 Further, the mechanical mode of oscillation dispenses with 

 the necessity for the steel writer, and a light grass awn, or a 

 hair-drawn glass fibre, can take its place. In the Resonant 

 Recorder the magnification is limited by the proportions 

 of the writing lever, usually to 25 times or thereabouts ; 

 but now in the Oscillating Recorder with a single lever 

 this may easily be raised to 100 times, and with com- 

 pound lever to 10,000 times. The Oscillating Recorder, 

 moreover, admits of lateral extension, so as to carry four 

 plates, and it may have as many plants recording 

 themselves side by side at the same time under identical 

 conditions. 



It is now time to see what results they have yielded. 

 First of all they afforded complete verifications of the 

 essential accuracy of the curves of plant-movements given in 

 the ' Plant Response ' taken by the simpler method of the 

 Optical Lever. The phenomena of nervous impulse were 

 demonstrated by the ' Resonant Recorder 'against the 

 generally accepted view that there was nothing in the 

 plant comparable to the nervous system in animals. Bose's 

 results were thus so convincing that the Royal Society 

 accepted them for publication in their ' Philosophical 

 Transactions ' (1913). Following this and the publication 

 of his ' Researches on Irritability of Plants/ Bose received 

 several invitations to lecture before different Universities 

 and scientific societies of Europe and America, and was 

 accordingly sent by the Government on his fourth scientific 

 deputation in 1914. 



Bose determined not only to carry his delicate instruments 

 but also the plant-specimens Mimosa and Telegraph- 

 plant (Fig. 13) from India, so that they should give their 

 autographic records before the audience. In Europe most 

 of the plants go through their periods of hibernation in 



