U18(.'OVERIES IN THE CELESTIAE SPACES). *S\\) 



telescoiiii inventore (1655). If the claim of priority be de- 

 termined by the periods at which offers were made to the 

 General States, the honor belongs to Hans Lippershey ; for, on 

 the 2d of October, 1608, he offered to the government three 

 instruments " by which one might see objects at a distance." 

 The offer of Metius was made on the i7th of October of the 

 same year ; but he expressly says " that he has already, for 

 two years, constructed similar instruments, through industry 

 and thought.'' Zacharias Jansen (who, like Lippershey, was 

 a spectacle maker at Middleburg) invented, in conjunction 

 with his father Hans Jansen, toward the end of the sixteenth 

 century, and probably after 1590, the compound microscope, 

 the eye-piece of which is a concave lens ; but, as we learn 

 from the embassador Boreel, it was not until 1610 that he 

 discovered the telescope, Avhich he and his friends directed to 

 distant terrestHal, but not toward celestial objects. The in- 

 fluence which has been exercised by the microscope in giving 

 us a more profound knowledge of the conformation and move- 

 ment of the separate parts of all organic bodies, and by the 

 telescope in suddenly opening to us the regions of space, has 

 been so immeasurably great, that it seems requisite to enter 

 somewhat circumstantially into the history of these discov 

 eries. 



When, in May, 1609, the news of the discovery made in 

 Holland of telescopic vision reached Venice, Galileo, who was 

 accidentally there, conjectured at once what must be the es- 

 sential points in the construction of a telescope, and imme- 

 diately completed one for himself at Padua.* This instrument 



* Tlie above-iiaoied pliysiciciu and mathematician of the Margravate 

 of Aiifbach, Simon Mariiis, after receiving a description of the action 

 of a Dutch telescope, is likewise believed to have constructed one him- 

 self as early as the year 1608 On Galileo's earliest observation of the 

 mountainous regions in the moon, to which I have referred in the text, 

 compare Nelli, Vita di Galilei, vol. i., p. 200-206 ; Galilei, Opere, 1744, 

 t. ii., p. 60, 403, and Lettera al Padre Cristoforo Grienberger, in mate- 

 ria delle Montuosita delta Lnna, p. 409-424. Galileo found in the moon 

 some circular districts, sutrouuded on all sides by mountains similar to 

 the form of Bohemia. " Eundem facit asjiectum Lunte locus quidam, 

 ac faceret in terris I'egio consimilis Boemite, si montibus altissimis, inque 

 periphenam perfect! circuli dispositis occluderetur undique" (t. ii., p. 

 8). The measurements of the mountains were made by the method 

 of tjie tangents of the solar ray. Galileo, as Helvetius did still later, 

 measured the distance of the summit of the mountains from the bound- 

 aiy of the illuminated portion, at the moment when the mountain sum- 

 mit was first struck by the solar ray. I find no observation of the 

 lengths of the shadows of the mountains. He found the summits "in- 

 circa miglia quattro" in height, and " much higher than the mountains 



