ON A TABLE OF STANDARD AVAYE LENGTnS OF THE i>J'ECi]:Al. JIN . 12 J 
TABLE Y. 
7,000 GRATING KEVEUSED 
(23) I 6 ob. Nov. 15, 1884. Excellent set. 
5896.158 5890.189 4703.1G4 4001.509 4';;h».;{-J1 4(.^...71(^ 
Hence * io- bh = 10S.585 
(24) f 4 ob. Excellent set. 
4508.461 4501.444 5624.770 5624.254 44:t7.048 41L'1.711 
Hence 5y - 4^? = 13.512 
(25) I 4ob. 4222.309 5270.506 52(;9.725 4215.G70 
Hence 56- 4/ = 11.635 
(26) I 4 ob. 
5914.380 4222.382 4924.946 4924.110 4215.067 589C.1G1 5800.1^- 1 ITL' 
Hence 5 o - OJ = - 50.920 ; 6^ - 7e = -28.115; 7e-5o = 79.035 
(27) ^ 6ob. 5270.501 5269.713 4376.107 
Hence 5Z- 6/= 93.893 
(28) f Cob. 
5914.389 5896.151 5890.190 4703.160 4691.569 4690.318 5862.5«6 5S59.S15 4GSa..a'.* 
Hence 4o - 5 A = 108.596 
(29) I 4 ob. 
6569.455 4924.953 4294.109 6563.050 6546.494 4903.477 4859.911 6ir.-j.799 4824.291 
4823.667 
Hence 3 ^ - 4/ = 28.704 
(30) I 6 ob. 
6 
6594.108 6593.164 5270.500 5269.720 6569.438 6563.000 6250.«25 5250 HO* 4376.loO 
Hence 4 r - 4 j = 109.548; 4^ - 5^ = -85.554; bl-6f= 93.950; 4^-6/= 8.«J0 
(31) I 12 ob. Excellent. 
6884.080 5162.456 
SIX-INCH CONCAVE GRATING. 21i FEET FOCUS. 
10,000 lines to inch. 
I Slit wide open to see A, so that definition ^vas i>oor. 
^■^ ^!^' !::^:::!: 
5068.943 
7621.245 5083.513 6090-9'- 
