WILLIAM CRANCH BOND. 



227 



owing to the will but, comparatively speaking, to the poverty 

 of the college. 



" This result followed, however, that, upon his return, Mr. 

 Bond constructed the model of an astronomical dome, the 

 operative plan of which was the same as that of the great dome 

 built in 1844, and which has been in satisfactory use at Cam- 

 bridge to the present time. The chief peculiarity of its 

 mechanism is in the method of rotation by means of smoothly 

 turned spheres of iron. The dome rests on these at equidis- 

 tant points, and, being set in motion by suitable gearing, the 

 iron balls sustaining its weight roll along a level, circular track 

 of iron, the circumference of which is equal to that of the 

 dome. The method was unlike that previously in use. It ap- 

 pears to have been original with Mr. Bond, as is perhaps 

 evinced by a remark in his report for 1848 referring to the 

 matter : * If carefully examnied, it will be found that this 

 arrangement is as perfect in theory as it is appropriate and 

 convenient in practice.' Experience has shown that spheres 

 of hard bronze are more serviceable than those of iron, and 

 bronze is now used." 



While Mr. Bond was abroad, he married, July 18, 1819, his 

 cousin, Selina Cranch, of Kingsbridge, in Devonshire. Return- 

 ing home, he went to live in Dorchester near his father's resi- 

 dence in a house which he bought. On these premises he 

 erected, about 1823, a small wooden building which he care- 

 fully equipped for astronomical observations. This building 

 is the one mentioned in the official reference to the " observa- 

 tory at Dorchester " found in various publications. Its posi- 

 tion, as given,by Mr. Bond in 1833, was o 3' 15* east of Har- 

 vard Hall in Cambridge. 



Mr. Bond now advanced rapidly in his favourite pursuit. 

 "As soon as his circumstances permitted," writes his son, "he 

 imported more perfect apparatus from Europe, and continued 

 to add to his collection until it was the best in the country." 

 In his little observatory "no eclipse or occultation escaped 

 him, though occupied in business during the day in Boston." 

 After gathering for several years materials for investigating 

 the comparative rates of chronometers at sea and on shore, he 

 presented a paper to the American Academy in which he 

 effectually disposed of the scientific question involved, so far 

 as it related to the interests of navigation. Mr. G. P. Bond, 



