other foundation than the air. The space between these objects and the horizon having a grey pellucid tinge very distinct from the darker colour of the sea. This deception of the atmosphere, as far as it affects the relative positions of the heavenly bodies with regard to the eye, is a subject which has been much attended to by astronomers, and tables have been constructed to obviate the errors it occasions, which are perhaps as accurate as the difficulties in which the subject is involved will permit, but as the deception affects the visible horizon and other objects on the earth's surface, it seems to merit a still more strict investigation, as it produces great incorrectness, particularly in warm latitudes, with respect to all observations taken by means of the visible horizon, as well as in those geometrical admeasurements which depend on a distant object, and are to be ascertained with a theodolite, or other instrument on shore. On this account an artificial horizon possesses decided advantages over the visible one in point of accuracy, and is, whenever it can be used, to be greatly preferred.[1]
In the evening, the Captain having completed his stock of water, a precaution which it is advisable for every ship to take at this place previously to entering the Red Sea, I returned to the Marian, after having had the trouble of settling my account with the Banians. Though these traders possess a remarkable suavity in their manners, and an immoveable command of temper, yet there are no individuals in the world more keen, artful, and rapacious in their dealing, and consequently in all communications with them undue exactions must be expected and carefully guarded against, notwithstanding there may be an appearance of minute and scrupulous accuracy in their accounts. This may generally be best effected by mild behaviour, yet unalterable steadiness in resisting their impositions. With respect to other points of character, I have been induced to think, from what I have witnessed, that they are a quiet, and estimable people; and even in that point, which I have seen reason to condemn, some allowance ought to be made in their
- ↑ I am informed that a very satisfactory explanation of the various effects of refraction has been given in the Philosophical Transactions by Dr. Wollaston.
