•70 Mechanical FhilosophT/. 



lity to navigators, were also formed soon after 

 Harrison's, by Kendal, Arnold, and others of 

 Great-Britain, and by several distinguished French 

 artists. The happy effects of these discoveries and 

 improvements in aiding navigation, and, of course, 

 their favourable influence on commerce and the 

 interests of humanity, are so obvious as not to re- 

 quire formal explanation. 



But no age, assuredly, can vie with the last, in 

 the accuracy and astonishing powers of the astj^o- 

 noviical Instruments which it produced. The prin- 

 cipal ones, among those of an optical kind, were 

 mentioned in a former part of this chapter, and 

 need not be again recounted. In addition to these, 

 many curious instruments and machines, serving to 

 illustrate and exemplify the principles of astro- 

 nomy, have been devised by ingenious men. The 

 first deserving of notice is the Orrery, invented 

 by Mr. George Graham, an English mathema- 

 tical-instrument-maker, and presented to George 

 I.'' The next is a machine, under the same 

 name, contrived by Mr, James Ferguson, also 

 of England, and including some improvements 

 on the former. To these succeeded a Planeta- 

 rium, of very curious structure, by Mr. William 

 Jones, of London, and the celebrated astro- 

 nomical Sphere, by Dr. Long, Professor in the 

 University of Cambridge; to say nothing of a 

 multitude of other inventions of a similar kind, by 

 different artists and astronomers. But among all 

 the contrivances of this nature which have been 

 executed by modern talents, the machine invented 



e The origin of the name given to this machine is as follows. Mr. 

 Rowley, a mathcmatical-instrument-maker, having obtained one from 

 Graham, the inventor, to be sent abroad, with some of his own instru- 

 ments, he copied it, and made onefor the -£^r/ o/Orrer v. Sir Richard 

 Steele, who knew nothing of Mr. Graham's right to the invention, think- 

 ing to compliment the noble encourager, called it an Orrery y and gave 

 Rowley the praise due to Graham. 



