1793.
January
a good opportunity of making such observations as were required to prove the rate of the chronometers. At noon the latitude was found to be 36° 23′; Kendall's chronometer shewed 238° 18′; Arnold's No. 14. 238° 7′½; No. 176, 238° 10′¾, and Earnshaw's pocket watch, 238° 3′. In this situation the southernmost land in sight bore by compass S. 56 E. : an apparently detached piece of land like a small islet, S. 72 E.; and point Pinos N. 31 E. This point, according to our observations made on shore at Monterrey, is situated in latitude 36° 38′, longitude 238° 22′; from which it appeared that the chronometers, since they had been taken onboard, had acquired the following errors, (viz.) Kendalls 13′. Arnolds No. 14, 2′ 30″ ; Arnold's No. 176, 5′ 45″, to the east of the truth. Earnshaw's pocket watch appeared to be correct. By these observations Kendall's had acquired the greatest error, and Earnshaw's had gone perfectly right. The great regularity of Kendall's hitherto made it difficult to account for this sudden alteration, which could be attributed to nothing but the change that had taken place in the climate on their being removed from the shore to the ship. The thermometer was found daily to vary at the observatory between mid-day and the evening, from about 72° to 40°; the excess was more, as it would sometimes rise to 76°. and fall to 31° ; but this did not frequently happen, though early in the mornings it was not unusual to find the little wells we had dug skimmed over with thin flakes of ice, and the ground covered with hoar frost. On board the ship, the mean temperature of the air in which they were kept was between 54 and 60 degrees. This opinion appeared to be particularly corroborated in the instance of Kendall's watch, which evidently went nearly at its Nootka rate during our passage from thence to Monterrey; but on its being there landed, the increase and continuation of the cold appeared soon to accelerate its motion from that of gaining 11′¼ to 18½ per day. On allowing its rate of gaining at Nootka, from the time of its last coming on board at Monterrey, it was found to agree very nearly with the longitude of point Pinos, as affixed to it by our observations; and as I am perfectly satisfied of the accuracy of our observations, the difference can surely be attributed to no other cause,than
