46 TiiANSACTroxs of the American Ixstitute, 



a telling fact, that this wonderful emanation is poured upon the most 

 delicate organ in its own way in the system with a velocity which 

 would accomplish 250 days' journey by steam in a single second. 

 One would suppose that, poured upon that most delicate organ with 

 that fearful velocity, it would thereby extinguish it forever, I*To, 

 Truly the light is sweet, and a pleasant thing indeed ; it is for the eye 

 to behold the sun, and that simple, natural declaration of the wise man 

 of Israel is responded to in the feelings of every one who once has 

 had the benediction of being able to see. Kow, the benediction of 

 both the noble senses is two-fold. In the case of light we not merely 

 perceive brightness, and learn to judge of its forms, and also catch 

 expression, but we have the additional benediction of color, and all 

 til at belong to it. So with regard to the other noble sense of hearing. 

 "We are not restricted to the mere perception of sound, or even the 

 sentiment of conversation, but we have both the melody and harmony 

 which belong to music. In each of the noble senses, then, the bene- 

 diction is two-fold. But now we have not to do with mere seeing. 

 The ancient observations of astronomy have been well described as 

 those which required merely eyes, and attention, and patience, and 

 time. We are to speak of that admirable exterior eye — an artificial 

 eye — a noble present from optics to astronomy — one of the grandest 

 we have ever had. We are to discourse of the telescope, and before 

 we do so it may be as well to give you some idea of what constitutes 

 a telescope, and how light is acted upon. [The lecturer here 

 explained at length the principle upon which the telescope is 

 constructed, illustrating his subject by the use of diagrams, etc.] 

 "We now come to the history of the telescope. I have here a printed 

 book containing an article by Prof. Alexander, and as he is a per- 

 sonal friend of mine (laughter), I will quote from it. He spoke of 

 Itoger Bacon as having invented spectacles, possibly in the thirteenth 

 century : " Roger Bacon (to whom allusion has already* been made), 

 in his Opus Majus, makes use of such language with reference to 

 what ' may be performed by refracted vision,' as to render it some- 

 what probable that he was at least acquainted with the theory of a 

 refracting telescope, though there is no sufficient proof that he con- 

 structed one ; and Baptista Porta is said by Wolflus to have made a 

 telescope, but the description of the instrument given by the inventor 

 is very defective, and the instrument, whatever it was, does not seem 

 to have been used in any celestial observation. Indeed, ' we have no 

 distinct evidence that such an instrument was used before the begin- 



