MEMOIR OF DANIEL TREADWELL. 493 



Respectfully dedicated to the engineers of the twentieth century by the author. Cam- 

 bridge, July, 1864." Below this is the following: "This work, written in the middle 

 of the nineteenth centurj' by an engineer who was born in the eighteenth, is pater- 

 nally and lovingly dedicated to the children of his profession who may live in the 

 twentieth." 



Still he writes to Dr. Sweetser: "Time passes quieth*, but I cannot say that it 

 goes happily. The want of success in mj^ gun leaves a murk which it will be hard 

 to rub out." 



The civil war was to him a sore trial. To Dr. Sweetser he writes, " The Union split 

 in two and the Constitution gone ! Alas for the great Republic ! " He saw in the 

 future only border warfare and ruin to a once prosperous nation. Fortunately he lived 

 to see the war ended, and his country gradually recovering from its dreadful calamity. 



The tendency of his mind was essentially experimental. " He had the ingenuity 

 of the mechanical inventor, and the philosopher's passion for truth." Difficult me- 

 chanical problems seemed to have for him a strange fascination, from which he was 

 only to be delivered after he had reached a satisfactory solution. He was an excellent 

 experimenter, and a skilful handicraftsman. It must have been rare that a conclusion 

 at which he had arrived by experiment was successfully attacked. He seems to have 

 been of John Hunter's mind when Edward Jenner asked his opinion of a theoretical 

 solution: ''I think your solution is just. But why think? Why not try the experi- 

 ment ? Repeat all the experiments, and it will give you the solution." He might 

 have said with Leonardo da Vinci, '• Instrumental or mechanical science is the most 

 noble, and of all the most useful, seeing by means of it all animate bodies that have 

 motion perform all their operations." 



Mr. Treadwell did not place a verj' high value on scientific knowledge alone, as 

 leading to great mechanical inventions, but was well aware that tho.se who have made 

 such inventions have been under the influence of the knowledge of the age, and re- 

 ceived aid from their acquaintance with focts which had been disclosed by scientific 

 investigations. The peculiar combination of qualities intellectual and moral to give 

 effect to scientific knowledge so far as this has been required to produce the great 

 practical results witnessed within the last hundred years, he thus enumerates : " It is 

 a combination of clear and active perceptive fiiculties, high imaginative power, a great 

 faculty of comparison, a determined will, and a never tiring perseverance, together 

 with knowledge at the disposal of the imagination which can create and combine 

 shapes never before seen, and trace the course of motion through series of bodies 

 never before combined." These qualities he possessed in a marked degree. 



As to his religious belief, "his was a mind in which science seemed to have taken 



