Papers on meteorology : relating especially to the climate of Britain, and to the variations of the barometer / by Luke Howard.

  • Howard, Luke, 1772-1864.
Date:
1850-1854
Catalogue details

Licence: Public Domain Mark

Credit: Papers on meteorology : relating especially to the climate of Britain, and to the variations of the barometer / by Luke Howard. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    that of its greatest and extraordinary elevation, to 30 89, on the 7th of the second month [February] at the time of the last quarter. Moreover, this coincidence ap- peared to obtain the most regularly in fair and moderate weather; and, in general, when the barometer fell during the interval between the new or full moon and the quarters, an evident perturbation in the atmosphere accompanied; of which may be instanced II [February] 15 to 23, when the barometer, after an uncommon rise, con- tinued to fall rapidly after the new moon, with severe cold, which ended suddenly in stormy and wet weather; again VI [June] 14 to 20, when two weeks of fair weather ended in a thunder-storm. In the greater part of XII [December] the usual coin- cidence disappears, and the converse takes place; the barometer being low at the quarter and high at the full, amidst continued alternations of rain, frost, and snow; and, for part of the time, high winds. The remarkable depression between the 24th and 28 th was attended with intense cold, the thermometer being noted on four suc- cessive days at 15°, 14°, 9°, 13°, respectively. On the two days preceding the last quarter, the barometer rose rapidly, and rain followed ! In the seventh month [July], which was wet and windy throughout nearly, there is the least of this coincidence to be seen. Instances may be observed in which the tendency to rise or fall at the times pointed out, after being interrupted by an occasional cause, is resumed. On the whole I thought there appeared sufficient ground, on the evidence of the year 1798, to suppose that the gravity of our atmosphere, as indicated by the barometer, may be subject to certain periodical changes, effected by a cause more steady and regular than either change of temperature, currents, or solution and precipitation of water, to which I believe the whole variation has been heretofore attributed. To discover these periodical changes, if possible, and to ascertain their amount inde- pendently of the operation of the last-mentioned causes, I took the following method : Passing regularly through the register of the barometer which I had chosen for examination, I extracted one observation for each lunar week, as near as possible to the time of the change, which I ranged under its proper title, either new moon or full, &c. Having gone through the year, I took the mean of the whole of these notations, and afterwards the mean of those under the title of new moon, full moon, first and last quarter, respectively; by comparison of which with the general mean I attained my object.” The Register having been examined in this manner, the results were as follows: Mean of the Whole. Full Moon. Last Quarter. New Moon. First Quarter. 29-9638 29-906 30-153 29-719 29 980 Difference . . . -0-578 +T892 -'2448 + -0262