Keith Lucas. 



xxxm 



tions. He felt the importance of this work, and, with his knowledge of the 

 diflBculties of the subject and his power of clear explanation, it was natural 

 that he should be a most successful teacher. The work he had himself done 

 in Physiology, and his hope for far greater advances, both by his own work 

 and the work of others, inspired in his pupils enthusiasm for further 

 investigations. 



In 1909 Keith Lucas married Alys, daughter of the Kev. C. E. Hubbard. 

 He leaves three sons. He became a Director of the Cambridge Scientific 

 Instrument Company in 1906, and only resigned in 1914, when he joined the 

 Royal Aircraft Factory. During this time he designed many instruments 

 both for teaching and research. 



Even when he was in New Zealand, and before he had begun his original 

 scientific work at Cambridge, and had so much to do witli the design of scientific 

 instruments, he thought that the great flaw in instrument making was that 

 there had to be much perfect and expensive workmanship to make up for 

 faults in design. He agreed with the definition of a well designed instru- 

 ment as one which worked smoothly and well, and gave accurate results 

 when the rubbing surface became worn or the parts damaged, and even 

 if badly made. In his designs, each moving piece was allowed only the 

 requisite freedom to move in the proper manner, and was guided only at 

 the correct number of points. The importance of these considerations was 

 long ago pointed out by Clerk MaxweU and Lord Kelvin, and generally leads 

 to a good design as defined above. 



In his work with the capUlary electrometer, he had to analyse a great 

 number of photographic curves; to do this he designed an instrument 

 which saved a great deal of time, and gave results with remarkable 

 accuracy. In connection with this work, he designed a rapid and trust- 

 worthy method of drawing fine capillary glass tubes. He also designed a 

 photographic time-marker on the principle of the Einthoven string 

 galvanometer, in which the self-induction and inertia were much reduced, 

 and the time -lag was extremely small. Among other instruments, he 

 designed apparatus for breaking two electric contacts at short intervals 

 apart, and many useful instruments for teaching. 



Like so many of the best experimenters, he made with his own hands 

 much of the apparatus he wanted for research, and his skill allowed him to 

 use the simplest means to get good results. Some of the more elaborate 

 instruments, however, were made by the Cambridge Scientific Instrument 

 Company, and he often discussed the designs with me, as Chairman of the 

 Company and as his personal friend. This was always a pleasure ; he 

 knew what the instrument should do and how the parts should be made, and 

 his quickness in reaHsing the difficulties, and in seeing improvements in a 

 mechanical design, was most striking. Sometimes I felt proud that I was 

 able to improve the work of such a master of the art of design. If this 

 happened to be the case, his quickness and fair-mindedness made him 

 realise the fact at once. If it were not so, he very soon proved that he was 



