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she advances towards the Equator. To make this more clear, let us take the average of rain-fall on the days when the moon's declination is great, and compare them with those when it is less, and we shall find the following results.

In August, 1823.

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The average rain-fall for each day, when the declination of the moon (either south or north) was greater than 180 was 0.826 inches. When the declination of the moon was between 180 and 9o it was 0.330 When the declination of the moon was between 9o and 0° it was 0.174 In September.

0.151

When the declination of the moon was above 18° it was........ 0.656
When between 180 and 90,
When between 90 and 0°,

....

0.297

An exception to the former observation will be noticed here, since in September, the average, when the moon is between 9° and 0°, exceeds that when she is between 18° and 9°. This I take to be owing to the course of the sun, whose declination is between 9° and 0° in the month of September, and at that time of year, the days when the declination of the moon is within those limits are also the days of conjunction and opposition. As the divisions I have adopted for illustration are merely arbitrary, any others may be substituted for them. Thus, if we take the average (for the two months) of the days of maximum declination of the moon, of one day before, and two days after that, we get an average of 1.17 inches for each day. In this case, there is an excess, probably owing to the locality of Calcutta, a place which having a great extent of ocean to the south, is more exposed to the influx of currents from the ocean, when the moon gets to the north of it. But on this I hope to be able to speak farther hereafter. In the period included in the table there are six days, on each of which the rain-fall was greater than two inches. I here subjoin them, with the corresponding declination of the moon.

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I have also been able to obtain the registers for the last two

months of the year 1824, and for the first three months of the year 1825. In this period a few items of rain are registered, which are as follow :

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TABLE—Shewing the quantity of Rain in Inches and Decimals that fell in the months of August and September, 1823, with the Declination of the Moon, to the nearest minute, at noon, on the corresponding days, also her Semidiameter ditto, and Sun's Declination ditto.

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It may be observed that (with one exception) the items of rain, which fell with a low declination of the moon, in the two last months, may be attributed to the effect of the conjunction and opposition of the sun. Should this predominance of rain about the maximum declination of the moon be found to obtain generally, it will account for the third day before the new moon, and the 11th and 12th after, being maxima-a circumstance which I noticed in my former paper, but was unable to explain. The rainy-season lasts more or less from the 21st June to the 21st September? Now the day of new moon nearest the 21st June is nearly or actually the same with that of maximum north declination. But as the sun leaves the northern tropic, the days of maximum declination gradually separate from those of conjunction and opposition, till by the time he is at the equator, they have reached the quarters.

In adding up, therefore, the sums of rain which fell in successive lunar revolutions, the chances were, that the third day before, and 11th and 12th after, new moon, would be the maxima, as they were (upon the whole) nearest to those of maximum declination of the moon. I hope shortly to obtain a sight of the Nautical Almanacks for some other years, and to have the honour of laying the results (whatever they may be) of a comparision of them, with the registers, before the Society. It only remains for me to explain, why I preferred comparing the amounts of rain-fall, and the fluctuations of the dew-points with the changes of the moon, to comparing the heights of the barometer with the same, and as this latter plan has been suggested to me from a highly esteemed quarter, I lose no time in replying. I first beg to refer him to DANIELL'S Meteorological Essays, (1829), page 136, and to assure him, that I agree with the observations there made, viz. That the total weight of the perpendicular column would not be affected so much as that of its horizontal sections; and the amount of the lunar influence should be sought in the variations of the differences of density between some high elevation and the level of the sea," &c. For example, supposing a case where the aërial fluid was at rest (the pressure being equal every where). Now, if any inequality were to be caused (either by the presence of a luminary above the horizon or otherwise) a current would instantly be set in motion to restore the equilibrium, and any inequality, beyond what was necessary to overcome the inertia of the air, would instantly be counteracted by an increased velocity of current. But in estimating the rain-fall and dew-points together, we get the sum of the effect produced-the accumulated results of successive tides or currents. If we reflect what a small difference of level is sufficient to set water in motion, we cannot

but suppose that a very small inequality of pressure would be sufficient in the case of air. Such an inequality is no doubt caused by the action of the moon. Mr. HOWARD found, on an average of 10 years at London, that the barometer stood 0.10 (I quote from recollection) lower at change and full, than when the moon was in the quarters. No such inequality could be found in this climate, though a difference to a small amount may be detected. If the Editor will refer to the Table No. 3, annexed to my last paper, he will see that I did attempt such comparisons as he speaks of, with the barometer; but left them off, owing to the results being less satisfactory than those derived from the rain-fall and dew-points. I must acknowledge that it is by the indications of the barometer alone, that we can ever hope to include the atmospheric changes within the precise limits of a mathematical formula; but if we are precluded from this, we are not therefore debarred from adopting a more indirect and humble line of investigation, which, though it can claim no praise for ingenuity of research, may yet present us with some results of general usefulness. If we can obtain one additional presage of an approaching storm-if we can indicate with some probability the year of drought and famine, our time has not been misemployed, nor our labors wholly fruitless.

I perceive that the effect of the moon's declination is felt in the rain-falls in England, though but slightly, as was to be expected.

VII.-Correction of a mistake regarding some of the Roman coins found in the Tope at Manikyala opened by M. COURT. By Lieut. ALEXANDER CUNNINGHAM, Engineers.

[We hasten to insert the following extract from a letter just received, as the corrections pointed out appear to be in every case judicious,-in the case of Lariscolus conclusive. We compliment our young friend upon the success with which he has commenced his numismatic studies, and shall always be happy to profit by his criticisms.-ED.]

I take the liberty of addressing you on the subject of the coins found in the second tope at Manikyala by Mons. COURT, as I conceive you have made a great mistake in the age of one of the Roman coins, and it is from this very coin that you fix the date of the erection of the tope. The coin I mean is No. 22. You remark that the helmeted figure on this coin and the unintelligible inscription on the reverse lead you to ascribe it to the age of the Emperor CONSTANTINE : now these very observations of yours, setting aside the appearance of the coin, convince me that it is of the time of the Commonwealth; and I take it to be one of the Gens Herenria, of which there are 15 varieties it may however be one of the Gens Quinctia, of which there

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are 12 varieties-but as I have no books for reference I shall be much obliged if you will look over the coins of the families, and settle the point. The style of the coin is exactly the same as those of the times of the consuls, and very different from those of the age of CONSTANtine. The obverse is either a head of Roma or of Libertas, and the ornaments upon the helmet are peculiar to the early Roman coins. The reverse is a common device upon the coins of families, and represents two soldiers fighting, with one fallen between them, while victory is hovering over their heads. You say of the two combatants that one is clad as a Roman, and query whether the other as a German : if the coin is of the age of CONSTANTINE, by what means has the German got there? My opinion is that the coin is one of Quintus Herennius, with perhaps the cognomen Marcomannus, or some other name obtained from the earlier enemies of Rome. At any rate the age of the coin can be decided by this-If it is a coin of the families, it must be pretty thick—if of the age of CONSTANTINE, thin.

The remaining three silver coins, you say, are in too imperfect a state to be identified: I agree with you that Figs. 24 and 25 are too much worn to be identified—though they both appear to me to be of the times of the consuls-No. 25 has the appearance of a Parthian coin. No. 23 you say ' bears the final letters of the word CÆSARIS'-but I think I can show that you are wrong. What you call the final letters of the word Cæsaris are the commencing letters of the man's name who struck the coin. The word is LARISCOLUS, which was the cognomen of Publius Accoleius. This coin is the only known specimen of the Gens Accoleia, and the whole inscription should be P. ACCOLEIUS LARISCOLUS-The reverse is a play upon his cognomen of Lariscolus or the Larch Tree; and although the coin is much worn, yet the three sisters of Phaëton may still be seen just commencing their metamorphoses into Larch trees.-The story is related by Ovid*.

Of these seven coins found in the second tope at Manikyála, not one can be proved to be of a later date than the birth of Christ. What is the inference? That the tope must have been constructed about the commencement of the Christian era; and the coins may have belonged to the soldiers of the army which ANTONY led into Parthia, and it is known from history that they lost most of their baggage on that expedition. If, as you say, the tope is of the age of CONSTANTINE, why were there no coins deposited in it of a later date than the birth of Christ, when it is well known that Roman coins of the second and

* See Edinburgh Encyclopedia, Art. Numismatology; the plate contains a fac simile of this very coin.-ED.

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