CHAPTER XII. 



A BRIEF ACCOUNT OF OUR WORK. 



ASTRONOMY. MAGNETISM AND METEOROLOGY. EARTHQUAKES. ORIGIN OP THE NATIONAL OBSERVATORY IN CHILE. 

 CONCLUSION OF OUR OBSERVATIONS. TAKE LEAVE OF THE GOVERNMENT. EXPEDITION OF LIEUTENANT MAC-RAE. 

 RETURN HOME. APOLOGETIC CONCLUSION. 



During the summer and autumn months succeeding our arrival, there was almost uninter- 

 rupted fine weather. From the 10th of December, when the equatorial was ready for use, 

 night followed night unrivalled in serenity ; and to the close of the first series of ohservations on 

 the planet Mars January 31 there were but four unsuited to work. Labor so continuous in 

 a climate as dry almost as an oven, told severely on unacclimated constitutions; and it was 

 soon perceived that the principal assistant must be temporarily released, or be broken down, 

 perhaps permanently. The opportunity to send him to Valparaiso for the meridian circle was, 

 therefore, a welcome one; and Messrs. Hunter and Smith recorded for me on alternate nights, 

 until the former was disabled by being thrown from a horse. All the aid then was from Mr. 

 Smith ; besides which duty, he became wholly charged with the meteorological observations for 

 every third hour between 6 A. M. and midnight. Within the forty-eight working nights em- 

 braced between the above dates, nearly 1,400 observations of the planet were accumulated ; and 

 by the time that this series terminated, the piers for the meridian circle were finally completed, 

 the health of Lieutenant MacKae re-established, and we were able to give undivided attention 

 to its erection and adjustment ; so that the instrument was ready for use about the middle of 

 February. 



But it must not be inferred that our nights from the 31st of January were passed idly. Ob- 

 servations for approximate place of the circle had commenced some days before, and extra hours 

 of every night were spent in becoming familiar with the details of the superb instrument that 

 Messrs. Pistor & Martins had sent us from Berlin ; and thus, by the time its adjustments were 

 perfected, both of us were expert in its manipulation. Beginning within 5 of the south pole, a 

 systematic sweep of the heavens was then commenced in zones or belts 24' wide. Working stead- 

 ily towards the zenith on successive nights until compelled to return below again to connect in 

 Eight Ascension, the place of every celestial body that passed across the field of the telescope, 

 to stars of the tenth magnitude, was carefully noted down. The space immediately surrounding 

 the south pole was swept in one belt of 5 by moving the circle, and each zone overlaps those 

 adjoining both in Right Ascension and Declination. Above the polar belt there are forty- 

 eight others making in all 24 12' of Declination; within which we obtained 33,600 observa- 

 tions of some 23,000 stars, more than 20,000 of them never previously tabulated. In these 

 determinations, and others for instrumental errors, longitude, &c., until the arrival of Mr. S. 

 L. Phelps, in September, 1850, to replace Passed Midshipman Hunter, who never became 

 available, Lieutenant MacRae and myself alternately passed from six to seven hours of every 

 night. From October, 1850, Messrs. MacRae and Phelps had the entire charge of the instru- 

 ment for zone observations. When an accident to one of its screws compelled the services of 

 both at the same time, until a new one was received from Berlin, I devoted every other night to 

 the examination of stars in the catalogue of Lacaille, and between the zenith and our upper zone, 

 which had never been re-observed. These, together with observations of the moon, planets, 

 stars selected from the Nautical Almanac, &c., number about 9,000 measures. As may be 

 supposed, the discrepancies between our estimations of the magnitudes of stars and those of 



