434 



KNOWLEDGE. 



November, 1910. 



circular metal (iron) caps. It rests on tweKe 

 of them, each, in consequence, taking one-tweltth 

 (if the weight of the mirror, no matter what 

 i)i)sition it ma\" be in. When the muror is set 



that the room-mate of one of their sons up at 

 Dartmouth is now observer here, and so he shows 



them, am 

 in the ni 



\dn. as 

 ;ht tmie. 



would 



directh- on edge, a band about the outside holds 

 it in place. It must be thus cNacth' weighted on 

 account of the tiexures in the glass, 

 spoil the definition. 



The light strikes the first 

 mirror primarily and from it 

 is Sent t(i the second, a flat 

 circular mirror, which is of 

 t\\ent\-four inch diameter, 

 and stands on a massive iron 

 column. This second mirror 

 is upright, but is racked back 

 so that it can set the reflection 

 in an\' direction. Thence the 

 ra\s are sent from it to the 

 third mirror, i.e., the concave 

 one. which does the enlarging, 

 acting substantially as does 

 the lens in an ordinar)- tubular 

 telescope. 



It is im|)ossible to reflect 

 from the first mirror direct tn 

 the third, as the light cannot be 

 caught so well, and the station 

 would ha\e to l)e constanth' 

 changed. This changing is now 

 done b\- the second mirror. 



I'ive-thirtN- p.m. is supper 

 time with the astronomers here, and one leaves 

 them to return to the mountain hotel and his 

 chalet. 



In the evening two Yankees, also on visit, find 



their guests, the Obser\ator\- 

 The moon seen through the 

 great mirrors is a si.^ht long to 

 be remembered. The liglit of 

 the orb falls full through the 

 two mirr<irs on to the thirtl. 

 which it fills with its image. 

 The visitors stand round this 

 third mirror and then look 

 at It through a little black 

 hand niagnif\'ing glass. The 

 craters and hills and the like 

 take on new interest and 

 beauty. 



Again, one mar\els at the 

 site. Here on the long tented 

 platform, which stands built out 

 into the canon, \\ith the mag- 

 nificent forested \'alle\ s in 

 the moon-light, black in tlie 

 shadows, but stretching on to 

 the far lights of Pasadona and 

 Los .\ngeles. At another place 

 .1 huge forest fire breaks the 

 night. Over all a magnificent 

 clear starry sk\-. with the rising 

 moon, surrounds this white 

 K-i'e is sonK'thing inspiring in 



this uniipie little mountain star camii. 



Next morning. Professor Ellerton. second in 



charge here, tells some interesting facts about the 



tented huildniL 



In the Mirror. 



place. Harvard, he states, had an observatory here 

 fifteen or sixteen years ago. When then the 

 Carnegie Institute was about to open an obser\'a- 

 torv, it tested several places hereabouts, trying 



