A brief Memoir of the late Walter Folger. 315 
the problem, and the engagement so diverted his mind from his 
infirmities that he speedily regained his strength. He immedi- 
ately applied all his influence to the encouragement of the use of 
this method among his fellow-townsmen, then universally en- 
gaged in the prosecution of whaling voyages. 'To numbers he 
gave personal instruction, and the first American ship-master who 
determined his longitude by lunar observations, is said to have 
been one of his pupils. 
Soon after this period, he busied his mind in designing a clock, 
which, while answering the ordinary purposes of time-keeping, 
should exhibit various phenomena connected with the solar and 
unar motions. Having completed the plan, he submitted it to 
his father, for whose judgment in mechanics he had the highest 
regard, and receiving his sanction, he commenced the work at the 
age of twenty-two, and devoting only his leisure amid other en- 
gagements, finished it in the course of the second year. This 
clock now stands in the family parlor a monument of mechanical 
ingenuity ;—brown with age and now somewhat antiquated in its 
appearance, it is still a wonder. Nothing but the glass which 
covers its face, owes its construction to another hand, and its me- 
chanical execution would be creditable to a professed workman. 
But its chief excellence is in the phenomena which it exhibits. 
The diurnal motion of the sun is represented by a circular metallic 
plate, so adjusted that it is seen through a slit in the dial plate, 
at a greater or less meridian altitude, as the declination changes ; 
rising and setting as in nature, and changing the time in conform- 
ity to the latitude, change of declination and equation on each 
day, giving also through the entire day, the time of his rising 
and setting and place in the ecliptic. ‘The moon is represented 
by a spherule exhibited to the eye in the same manner; but by 
having one hemisphere colored, and ocess much more 
complicated, shows with great faithfulness, not only the rising, 
Setting and sonthing of the moon, with the time of full sea at 
Nantucket ; but also the chief phenomena dependent on the obli- 
quity of the moon’s path to the ecliptic, and the revolution “ 
her nodes, such as the hunter’s and harvest moon, d&c. 
these involve a motion of the works through a period of eighteen 
years and two hundred and twenty-five days, and the wheel by 
of that year, the formation of the ring occurring precisely at sun- 
rise ; but these he never published. 
