8 AN ACCOUNT OF THE 



a mahogany tripod with a cast-iron mounting, having equatorial motion and ad- 

 justable to every latitude. It was counterpoised in all positions. The eye-piece 

 selected for use magnified 60 times, and the screen of glass was of a moderately 

 dark green color. The latter was not fitted on the rim of the former, but was held 

 in the hand so as to be removed at pleasure, and Avithout the risk of disturbing the 

 instrument whilst so doing. 



In anticipation of the difficulty which would attend micrometrical measures of 

 either kind during the very brief period the total eclipse would continue, a cross 

 of wires, at right angles to each other, was inserted in a perforated card disk, and 

 fitted to the eye-piece. Then, to facilitate the location of, and approximate to the 

 elevation of such solar protuberances as might become visible, a diagram was pre- 

 pared. Three concentric circles were drawn upon a page of the note book. The 

 inner one — to represent the moon — was of 4 inches diameter — a black continuous 

 line ; the outer ones respectively one-eighth and one-quarter of an inch greater, 

 but with broken lines. The inner circle was divided into equal segments of 22J° 

 each, the vertical diameter on the page to correspond with the zenith and nadir of 

 the station. The outer circles were to facilitate estimations in altitude of the 

 protuberances, by comparison with the visible lunar diameter, all of which was in 

 the field of the telescope. 



The night of the 6th and until daylight of the morning of the 7th September was 

 bright and faultless ; but just before sunrise, a few banks of hea-\-y cumuli formed 

 over and near the distant mountains to the eastward, the part of the sky least 

 obscured being in the direction of the sun. Some of the intermediate peaks became 

 enveloped in fog banks at the same time, whilst thin cirri stretched to near the 

 zenith. The wdnd was then from the westward and the atmosphere humid, under 

 the influence of which, the lower strata of clouds increased in numbers and den- 

 sity, and the sun continued invisible until after the eclipse had made considerable 

 progress. By 6'' SO" all the fog banks to the north and west were drifting towards 

 the valley of Olmos, and at 1^ there was no portion of the sky entirely unclouded. 

 Whenever the sun became momentarily visible during that period, the cusps could 

 not be satisfactorily seen because of the masses of vapor continuously rolling across 

 its disk. At about 7'' 15"° there was a striking change; the whole mass of cumuli to 

 the eastward was lifted towards the zenith, leaving that portion of the sky clear, and 

 it was only by close examination that a delicate film of vapor could be detected be- 

 tween us and the sun. At this period, the general light did not greatly differ in 

 intensity from that of the moon when nearly full, though its color resembled more 

 that from burning spirit than that of the sun. Both intensity and color changed 

 under the feeble and gloomy illumination with perceptible rapidity, and for a 

 minute before the first internal contact of the limbs, the hills near us appeared 

 of a black hue. 



At from twelve to fifteen seconds before the beginning of totality the entire lune — 

 then perhaps 35° in extent — broke up into masses of unequal length, showing de- 

 tached portions wholly separated from the rest by dark lines. The occurrence was 

 so sudden as to startle me, and although within the ten following seconds, the 

 remaining visible fragments had become brilliant globides of nearly equal size, they 



