By JAMES GLAISHER, Esq., F.R.S.

THE variations in the readings of the barometer at the Royal Observatory, Greenwich, are shown in the annexed diagram, including 46 days, ending the 30th of November, daring which period there have been several severe gales of wind on our | coasts, producing, as usual, distressing shipwrecks, attended with fearful loss of life.

The objects of the NATIONAL LIFE-BOAT INSTITUTION are so truly philanthropic and j co-extensive with the coasts of the British j Isles, that I believe a few remarks in the j Life-boat Journal on the readings of the barometer, during the period above named, cannot fail to be interesting to the gallant crews of its life-boats, and to our boatmen and fishermen generally.

The reading of the barometer from the 1st of October to the 15th day was always high, and every day above its average, frequently to the amount of 0 • 3 in. and 0 • 4 in., and on the 3rd day to 0-5 in. nearly. The direction of the wind, till the 8th day, was generally E. or E.N.E., and the greatest force of the wind during this interval was about 8 Ibs. on the square foot; but usually the air was in gentle motion. From the 9th day the prevailing direction of the wind was N. and N.W., but at all times weak in strength. On the 16th day it changed to the S.W., and the barometer reading descended below its average, and declined, as is shown in the accompanying diagram, to 28'71 at 3 A.M. on the 20th, on which day pressures, to 9 Ibs. on the square foot, took place. The reading of the barometer suddenly changed to an increase, and at midnight on the same day was 29 • 40 in., being no less than 0'69 in. increase in 15 hours. It remained some little time at this point, and declined to 28-90 in. by 9 P.M.

on the 22nd. From noon of the next da/, the 23rd, its general tendency, as will be seen by the diagram, was increasing; it passed above its average on the 30th, having been 14 days continuously below, and at times for 24 hours together, as much as three-quarters of an inch nearly. From the 23rd the course of the wind was mostly from opposite quarters, viz., S.W. and N.E., but at all times light, and sometimes the air was almost free from motion. The barometer reading continued to increase, though with frequent slight falls, till November 6th, when the reading was as high as 30|- in. or If in.

higher than on the 20th. On the 7th day, the reading began to decrease, and passed below its average on the 10th, it having been above this point from October 30, or 11 days, a part of which time it was for 24 hours together more than 6-tenths of an inch in excess. During the 13th and 14th days, the decrease was rapid, and the reading from noon on the 14th to nearly noon on the 15th, varied only between 28'61 in. and 28 • 64 in.; thus the decrease amounted to 1 • 9 in. in 8 days. At this time, at Greenwich, the greatest pressure we experienced was 3 Ibs. only; and it is very remarkable that with so low a reading of the barometer about London, there was scarcely any wind, whilst fearful storms were raging north of us. From the 15th, the barometer oscillated, but for the most part increased, and was 29-72 in. on the 19tb, whilst the air was in gentle motion from the S.W. and S.S.E. Like changes followed, but decreasing readings were greater than increasing, till the reading of the barometer again was very low, viz., 28-72 at 1 A.M. on the 26th, accompanied with S.W. wind, blowing with a pressure of 5 Ibs. on the square foot only.

From this time the readings increased, and on the 30th passed above the average, having been below during 18 days.

It cannot fail to be remarked that, at all times, when the reading of the barometer was above its average, the wind has everywhere been moderate in strength, but that the period of our recent heavy gales has begun shortly after the reading has descended below the average; these gales have also been the worst when the departures below have been the greatest, and the bad weather has ceased only on the average again being approached.

One fact may be learnt from these readings, and it is one I endeavoured forcibly to impress upon the fishermen of the Northumberland coast, when I first fixed the barometers there, that at no time, and particularly during the winter months, should the warnings of the barometer pass unheeded; for although the barometer reading may be low, and indeed unusually low in some localities, without the storm passing over these places, yet they may feel certain that bad weather or gales of wind are, at that very time, most likely raging not far from them, and which might suddenly visit their localities without iarther warning. It is remarkable, indeed, that about London the barometer was (see the diagram) no less than three times, a good deal below 29 inches, yet no storm of any moment visited us; but we have had sad evidence of the fearful storms then raging on our northern and eastern coasts; and one almost sees the agonies, and hears the cries of the drowning men, women, and chil- dren at Tynemouth and Shields, imploring help from the plunging life-boat, two of whose noble crew perished in their humane efforts to succour their perishing fellow-creatures.

All honour to these brave but nameless heroes, of whom England may well be proud; and well may we mourn over those who unhappily perish in their sacred work.

These sad wrecks were taking place all along our eastern and northern coasts, while we were in comparative calm.

I wish to impress upon all sailors and fishermen the necessity of care, when continuous declining readings of the barometer are proceeding, and, of viewing such a state of things as plainly indicating approaching gales, which may not visit their own localities, but yet may do so; and if fortunately an indicated gale does not visit them on any special occasion, not to place less confidence in the barometer warnings, but rather to be careful till that reading of the barometer be attained which is the average of the place.

It is an ascertained fact, that when great atmospheric disturbances take place, and great depressions of the barometer readings occur, particularly when sudden, that they are the certain and sure prognostications of the approach of storms ; such signs no fisherman or seaman can, I think, now be so unwise as to neglect; for the caution thus given to him, conjoined with his own knowledge of the storms of the locality with which he must be familiar, will probably save him and others from loss of life and property. The ROYAL NATIONAL LIFE-BOAT INSTITUTION, by placing reliable barometers (tested by me at the Royal Observatory, Greenwich) around the coast, and thus directly preventing loss of life, may not gain so much praise as when one of its life-boats saves a crew from the sinking ship, but I consider that it deserves equal credit for taking timely steps to warn our fishermen from going into that sea in times of danger.

And surely the public will not fail to appreciate fully the feelings which prompt the Committee of the Institution to prevent, as far as possible, the necessity of having recourse to the life-boat, by timely warnings to those who otherwise might need its valuable and ever-ready services.

Royal Observatory, Greenwich, 1 December, ISGi..