am. v.] DISSERTATION SECOND. 185 



gave the same colour must be arranged in a circle, the 

 centre of which was the point in the cloud opposite to the 

 sun. This, though not a complete theory of the rainbow, 

 and though it left a great deal to occupy the attention, 

 first of Descartes, and afterwards of Newton, was perfectly 

 just, and carried the explanation as far as the principles 

 then understood allowed it to go. The discovery itself 

 may be considered as an anomaly in science, as it is one of 

 a very refined and subtle nature, made by a man who has 

 given no other indication of much scientifick sagacity or 

 acuteness. In many things his writings show great igno- 

 rance of principles of opticks well known in his own time, 

 so that Boscovich, an excellent judge in such matters, has 

 said of him, " homo opticarum reruni, supra id quod patia- 

 tur ea aetas, imperitissimus." The book containing this 

 discovery was published in 1611. » 



A discovery of the same period, but somewhat earlier, 

 will always be considered as among the most remarkable 

 in the whole circle of human knowledge. It is the inven- 

 tion of the telescope, the work in which (by following un- 

 consciously the plan of nature in the formation of the eye) 

 man has come the nearest to the construction of a new or- 

 gan of sense. For this great invention, in its original form, 

 we are indebted to accident, or to the trials of men who 

 had little knowledge of the principles of the science on 

 which they were conferring so great a favour. A series of 

 scientifick improvements, continued for more than two hun- 

 dred years, has continually added to the perfection of this 

 noble instrument, and has almost entitled science to con- 

 sider the telescope as its own production. 



It will readily be believed, that the origin of such an 

 invention has been abundantly inquired into. The resulf, 



1 De Radiis Lucis in Vitris perspectivis et Iride. — Venetiis, 

 in 4to. 



