Such is life, fuch are the seasons ; round rolls the globe, and fwift flies Time; ever changing! yet wifely ordered by Almighty skill and every feeming inconvenience productive of extenfive, important, and multiplied advantages.

Paffing further enlargement on these subjects, I proceed to fay a few words on the SHAPE of the Earth. I think the rotation of the earth on its axis is clearly established; I think also the fittest shape for a rotatory body is evidently a round one: that the earth is round, is evinced by the following confiderations: (1) The fhadows of all round bodies are round also : reverse this, if you please, round shadows imply round bodies; -the shadow of the earth is round, as appears by every eclipse of the moon; this is the most confiderable effect of the roundnefs of the earth which appears to our fenfes, fince the outline of this circle answers to fome thousand miles in length on the furface of the earth. (2) The roundness of the earth is what hides diftant objects from us, when no other impediment is interpofed; as at fea, the curvature of the water prevents our feeing what is behind that curvature; but if by any means (as a tall maft) we may be elevated above the effect of that impediment, we are enabled to fee beyond it: this is fo notorious to every failor that it needs no proof. (3) The fame effect occurs when we ftand on the shore; the highest part of a ship is what first comes in view, advancing to us; is what last quits our fight, when going from us. This convexity not only attends large bodies of water, but also rivers if traced in their courfes, exhibit the fame appearance. On a river, a little be feen at a mile diftant; but if you ftoop down,

boat

may

lowering the eye pretty near to its furface, the water will feem to be elevated, and will conceal the boat. Nay, we are told by Baron Du TOTT, that in the Crimea, (4) The earth is as level as the fea, and that he faw the heads of men at a diftance just peeping above the horizon, and moving on along it, while the reft of their bodies was concealed by it. In fact, the only occafion of appealing to water, is because it is the most level, and not fubject to the rifings or hollows which contribute to deception on land. (5) The globe has been circumnavigated : now had it been other than round, the boldest prow could only have failed to its extremes; where it must have been blocked up by impaffable barriers, or have funk into fome profound abyfs.

But when we fay the earth is round, we affirm alfo that it is fomewhat more in circumference at the equator, than across from pole to pole: it is, I fay flatter at the poles, than at the equator; and with reafon, for at the equator, being the most rapid fuperficial motion of its daily rotation, both land and waters feem to have felt its influence; and to be affembled in confequence. This is proved by actual measurement; by which we find that a degree on the globe is not the fame space (but fomewhat larger) under the arctic circle, as at the equator; by the incorrectnefs of pendulums, which under the line lofe the truth given them in England; by the immenfe mountains; by the calculated height of the fea; and by the velocity of the marine furges; all agreeing to demonftrate the elevation of our globe at the equator, and its confequent depreffion at the poles: though the difference be but one hundred and eightieth part, or 178 to 179.

One

One of the strongest arguments for the rapid rotation of Jupiter (befide actual obfervation), is his fhape; which differs in measure between his poles, and at his equator, as, 12 to 13.

As to the heights of mountains or depths of vallies, they are not equal to the roughneffes on the furface of an orange; which yet nobody fcruples to call round.

If the earth is round, there muft be fome places whofe inhabitants are our ANTIPODES, i. e. whose feet are opposite to ours; for every place must have its Antipodes; fince all points on the furface of a globe, must have oppofite points: otherwise it implies chasms and breaches. It follows also, that at antipodial (or exactly oppofite) meridians of the globe, the parts of the day are contrary: morning to one, evening to the other; noon to one, night to the other. The feasons also are contrary in contrary latitudes, as already explained.

Thus have we noticed the principal particulars of our earth confidered as a planet. Is there not much pleasure accompanying fuch enlarged views of its general properties! In confidering all men as brethren, however diftinguifhed by various climates, or separated by local distances! O that the general viciffitudes of light and darkness, of heat and cold, of funfhine and clouds, of fair weather and tempefts, might promote equally general fentiments of humanity among mankind!

G

VI.

OBSER

OBSERVATIONS ON THE PLATES

FIG

Belonging to LECTURE

VII.

PLATE I. SHAPE OF THE EARTH.

IG. 1. and 2. These figures are examples of the application of the principle adduced in the Lecture, p. 147. A fig. 1. represents a ship failing from the Tower B. It appears clearly, that the lower parts both of the tower and ship are first concealed by the rotundity of the circle; and are totally invisible, while the mafts of the fhip and the battlements of the tower are yet difcernible. Agreeable to this idea, the figure C fees only the maft of the diftant veffel E coming to him, while he fees diftinctly the whole of D, which is nearer.

Fig 2. reprefents the fame effect in fhips advancing to land. A cannot as yet see any part of the mountain C, it being concealed by the circumference of the earth: while B enjoys a full view of it; the vifual ray paffing clearly over the earth's circumference.

Fig. 3. HORIZON. This fig. fhews that the fenfible horizon (i. e. what part of the earth's furface actually bounds our view) is juftly confidered as coincident with the rational, or celeftial horizon HO: for though to the figure A there