Meridian transit observations made at mouth of Rio Grande, &c.—Continued.

a Deduced from corresponding observations made at Greenwich observatory.

c Deduced from corresponding observations made at Radcliffe observatory.

e Clouds prevent further observations this night.

TABLE B.

Results of observations made at mouth of Rio Grande for equatorial intervals of 46-inch transit, by Troughton & Simms-illumination east.

Equatorial intervals of 46-inch transit, by Troughton & Simms-illumination east. (Ơ. N. Thom,

Collimation error of 46-inch transit, determined from observations made at the mouth of the Rio Grande, October 27, 28, and 29, 1853-illuminated end of axis east.

(C. N. Thom, computer.)

Sum.....

Mean collimation of middle wire (in time)

Do............do.......................(in arc)
Collimation of mean of wires (in time)..
Do............ .do....................(in arc)

....

Vol. 1
1—28

25)4.076 +08.163

+ 27.44

+0s.10

+1.50

TABLE C-Continued.

Computation of probable error of collimation of middle wire of 46-inch transit, by Troughton & Simms-illumination east. (C. N. Thom, computer.)

Determination of the value of one division of the level used with the 46-inch transit, (by Troughton & Simms,) from observations made at the mouth of the Rio Grande, August 19, 1853. Micrometer attached to zenith. Telescope No. 4. Val. of one rev. 43".82. (C. N. Thom, computer.)