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.

    8/174 (page 4)
    These differences are ascribed to the differing constitutions of the ocean and the atmosphere. “ The want of facts to prove the existence of diurnal tides, appears indeed at first view an insuperable difficulty; since, if these did take place, the barometer ought to indicate them, by rising and falling twice in each day, in a degree proportioned to the supposed weekly tide.” This also is referred to the difference of constitution of the two fluids, water and air. These views were developed by the author, and the observations upon which they were founded recorded, in an essay “ On a periodical Variation, of the Barometer, apparently due to the Influence of the Sun and Moon on the Atmosphere,” which was read by him before the Askesian Society*, of which he was a member, and pubhshed by its permission in the Philosophical Magazine for September 1800 (First Series, vol. vii. p. 355—363). It was accompanied by a chart, entitled “Course of the Barometer for the year 1798,” which was a fac-simile of the original register on a reduced scale. A translation of a portion of this essay was inserted by the late Professor Pictet, of Geneva, in his Bibliotheque Britannique (,Sciences et Arts, tom. xix. p. 227 ; Mars 1802). The author refers, in this essay, to a paper of which a translation had appeared in the Philosophical Magazine for March 1799 (vol. iii. p. 120), giving “ An Account of Toaldo’s System respecting the Probability of a Change of Weather at the different changes of the Moon.” With this paper he requests the reader to compare his own observations (written previous to his knowledge of Toaldo’s theory), “ as they mu- tually support each other.” Toaldo (who was a mathematician of some eminence, and Professor of Physical Geography and Astronomy in the University of Padua,) is stated (p. 126) to have “compared a diary of the state of the barometer, kept for many years, with the situations of the moon, and found the following result: 1st, that the barometer at the time of the moon’s apogaeum rises the sixth part of a line higher than at the perigseum; 2nd, that at the time of the quadratures it stands a tenth of a line higher than at the time of the syzygies; and 3rd, that it is a fourth of a line higher at the southern lunistice [greatest distance from the zenith] than [at] the northern ” lunistice, or nearest approach to the zenith f. * An account of the Askesian Society will be given in the latter part of this Appendix. t This result of Toaldo’s calculations is cited by M. Arago, in his investigation of the question, “ Does the Moon exercise any appreciable influence on our atmosphere?” inserted in the “ Annuaire du Bureau des Longitudes de Paris” for 1833, as one of those which establish the reality of the moon’s action on the atmosphere. With respect to the influence of the apsides, it agrees with the observations subsequently made by Mr. Howard, as stated towards the close of the present Section, page 18.