1891.] * ■*■ [Ruschenberger. 



The closing paragraph of this interesting lecture is here cited as a fair 

 sample of its style and tone. 



"I hope I have said enough to prove that for prosperity and security, 

 nations are mainly dependent upon the intellectual capacities and acquire- 

 ments of their citizens. We have never known or heard of one that has 

 not experienced its days of trial, and it cannot be supposed that our own 

 country, whose hills and vallej r s now rejoice in the possession of peace 

 and abundance, can always be exempt from calamity. If ever driven by 

 adverse fortune to fearful extremity, happy will it be for her, if, in that 

 day, like France at the crisis referred to, or like England — sustained dur- 

 ing her long and dreadful conflicts by the resources furnished through 

 her Watt— be rescued by her philosophers ! Let us, therefore, like 

 France, and the mighty people from whom we chiefly spring, use all our 

 efforts to foster and diffuse the arts and sciences, and to banish the word 

 impossibility from our vocabulary." 



Dr. Emerson delivered an address, June 1, 1843, at Laurel Hill Ceme- 

 tery on the completion of an unostentatious monument erected to the 

 memory of Thomas Godfrey. 



The reason for this tribute is stated in the address, substantially as 

 follows : 



One day while an ingenious young man, Thomas Godfrey, a glazier, was 

 replacing a pane in a window on the north side of Arch street, opposite to 

 a pump, a girl after filling her pail placed it on the sidewalk. Turning to- 

 wards it he saw that the image of the sun was reflected from the window 

 into the bucket of water, and from it back to his eye.* This simple ob- 

 servation led him to study the law of the reflection of light, and to invent 

 a quadrant with speculums to take the distances of stars which he supposed 

 might be of service at sea. The same year, 1730, he had made his re- 

 flecting instrument.! One was taken to the West Indies and used during 

 the voyage to ascertain the latitude. It was brought back to Philadelphia 

 before the end of February, 1731. The practical value of the instrument 

 was thus demonstrated. 



Although James Logan, in May, 1732, described the mariner's quad- 

 rant constructed by Godfrey in a letter to the celebrated mathematician, 

 Dr. Edmund Halley, then President of the Royal Society of London, he 

 did not obtain credit for his invention. It is believed that Dr. Halley 



* John F. Watson, in his "Annals of Philadelphia," states this incident somewhat 

 differently. According to his account, which seems to be accurate, Godfrey was glazing 

 at Stenton, the residence of James Logan, and noticed the reflection of the sun's image 

 from the window to a piece of fallen glass and from it to his eye. He immediately went 

 into Mr. Logan's library and took from the shelf a volume of Newton's works to con- 

 sult. Mr. Logan entered almost at the same time, and asked him the object of his 

 search, and was much pleased with Godfrey's ingenuity, and from that time became his 

 zealous friend. 



In those days glazing was done by soldering the panes into the frame work. Glaziers 

 were also plumbers, and did not paint. 



t He lentone to Joshua Fisher for trial in his surveys of the Delaware. See Watson's 

 " Annals of Philadelphia." 



