Memoir of Rev. John Prince, LL. D. 207 



of them, dated March 3, 1798, Mr. Jones says, " It is to you that 

 the Air Pump and Lucernal owe their present state of perfection 

 and improvement." In another, dated September 29, 179S, he 

 says, " In all respects I think you have made the Lucernal as com- 

 plete and as simple as it can be made." Under the date of March 

 4, 1793, Mr. Jones acknowledges the adoption of Dr. Prince's " very 

 useful and ingenious emendations" in the construction of the " astro- 

 nomical lantern machinery." 



Thus a constant intercommunication of friendly offices was kept 

 up for nearly forty years. The correspondence is creditable to the 

 Messrs. Jones in every point of view. On the part of Dr. Prince, 

 it contains a body of instruction such as can no where else be found, 

 and would be regarded as an invaluable directory, by all whose bu- 

 siness or whose pleasure it is to make use of the instruments of sci- 

 ence. 



When we consider the situation of Dr. Prince, conducting his 

 investigations and experiments in solitude, far removed from the 

 great centers of scientific research and observation, and having to 

 communicate with other philosophers by the tedious and unsatisfac- 

 tory means of epistolary correspondence beyond the ocean, it be- 

 comes truly astonishing to reflect upon the success and amount of 

 his labors. Until long after his great invention of the improved 

 air-pump, he had depended almost wholly upon his own toil and 

 ingenuity in the construction of scientific instruments, not having, 

 at that time, established a correspondence with the London ma- 

 chinists. He had, of course, to struggle against many inconven- 

 iences, from which a vicinity to the London workshops would have 

 exempted him. There is a great amount of floating knowledge 

 accumulated and mutually communicated where many persons are 

 kept for a long time employed in any branch of business, and which, 

 never being recorded in books, the self-taught and solitary operative- 

 will not be likely to acquire. 



The following passage, extracted from a letter written by Dr. 

 Prince to President Fitch, of Williams College, Sept. 24, 1795, 

 will illustrate the trials and difficulties to which he was subjected in 

 the construction of philosophical instruments — it refers to an equa- 

 torial. 



" On my return home, the ingenious young man, whom I have 

 always employed to do my brass work, and who had begun the 

 brass box for the needle, could not finish it immediately. His 



