196 Use of the Zenith Telescope in Determining Latitudes. 
[B.] 
Corrections for Refraction, to be used in correcting observations with Z. Telescope. 
Pa | ZENITH DISTANCES. es 
arc. |0° 30¢ |4° 10’ \9° 40' \13° 00! {15° 4017 50! | 19° 40" [21° 20" (220 50" 124° 1077259 257] 
of  } 00} +00 00 00 00 00 oo “00 00} +O -00 | 
I or ol or OI} *O1 Ol "OI ol oO ‘Or 
02 | -02 | ‘02 02 02| -o2 02 02 02)| 02 02 
30 | ‘02 | -o2 | -03 03 03| -03 03 03 03] :03] 03 
2 3 03 03 o4 04} +04 04 o4 04 04 04 
30} 04 | 04 04 o4 05} «05 05 05 05 05 05 
3 Bb 205 05 05 05 06 06 ‘06 06 
30 06 ‘O07 *O7 07 ‘07 07 
4 07 | :07 | +07 07 07 | +07 “08 “08 08 | -o8} +08 
30 |. ‘08 | -08 08 | -08| -08 | -o9 09 09 | -09| +09 
5 08 | -08 | :09 | -09 | ‘0g| -09 | +10 10 10] *10] ‘10 
aot Oy 10 POPS AFOT 410 10 II It II II 
6 19 | +40.) :160 11 lI II ll 12 12 12} 12 
So.F Uae srt 12 12] -12 12 13 13.4403 os 
7 12 | 12 | -12| «12 13} -13 13 14 14| +14) +15 
30°} *13 |- +13 13 13 14} -14 | <4 5 15| +15] +16 
8 14°| *14 | +14 14 15| -15 15 16 +16 | +16 17 
30.1. +14.) 14 | 215 15 | 16) -16 16 17 17 I 18 
9 19 f-*10 | 116 WO; oto l ae 17 18 18 | *18 19 
30 | +16 | +16} +17 17 17} +18 18 19 19} ‘19 20 
10 eke sto Se 17 18 18 19} +19 20 20 | *20 21 
30 | 18 | +18 | +18 19 1g| +20 20 21 Phe eee ts eae | 
Il 19| -19| -19| .20 | *20| -20] ar | -ar a2} *22| -23] 
30} *19 | -20 | -20°} sor | ear} sat | .22 22 3} ‘a3 
12 20 | :20 | +a aI 22 if 292 obo .93 23 -94| 24] +25) 
3o | .-2r |. -2ar 22 22 ‘ast 69d -24 24 5 291 us 
13 22 | +22 | +93 23 | -24| +24 | .25 25 2 26} +27 
; 30 Hs > 24| .24| -25} .25 | 126 7 | -27} +28) 
I 2 2 24 ae |= 364° a6) 55 2 128| +2 ay 
3o} 25 | +25] -25| .26| -27) -o7 38 28 9 ; 30} 
15 25 | -26 | -26} .27 | -27| .28 | 29 | +29] -30} °3r 3t 
30 -26 | .27 28 28 29 | .30 +31 32} -32 
16 27 | +27 | -28 29 29 f° 30 fo %3r 31 32} -33| 33 
30 | -28 | +28 |. -29 | +30}. +30]. +31} -32 32 33) +34] 34 
Se 29 | -29 | -30] -3o ait 33.) .33 34| +35} 35 
“8-30 | +30} 31} +3} +32} -33.] .33 | .-34 | 35} -36} *36 
18 31 | +31 31 32 Sab 34 -37| 37} 
3o f.-31 | -3a 33 “34 | 335 37} 38} 38 
19 32 | -32 34 | :35| -36| .36] -37| -38| °39| “4° 
30 | #33 |. +33} -34.| > -36. 36] .37 | -38| +39} ‘40} 4 
20 34 | -34} -35 34) -37 | .38 39 4o| *41| *42 
3o | “354 35 37 38| -38 39 40 41| *42 43 
a1 364 336] -37|° +38 | 38] “39 |: -40. | +d 2| 43) 44 
30 | :36 | -37} -38 -39| -f0 | -41 | +42 43] 44) “® 
22 37 | -38| -38| +39] -40] -41 |. -42 44\ 45) 4} 
30 | -38| -38} .39| 40 | -41|] -4a} -43 | +44} -45| “46| “47 
23 9| -39| 40} “4t | +49} -43 | 44 47| 48 
40 | -40| -4t | +42 |. +43). 44]. -45 | 46) 47} 748) 749) 
24 rj 4c} 42} -43 | -44| -45 | +461 -47 | 148) 7491 92h 
e same table may be formed as conveniently by differences 
from the usual refraction tables. 
In selecting the pair of stars for use with this instrument, we 
have found the following rules convenient or necessary to be 
served. The British Association Catalogue ged afforded ready 
means for their selection, and the computation of their places. 
a 
