Volume 1

The climate of London, deduced from meteorological observations, made in the Metropolis, and at various places around it / by Luke Howard.

  • Howard, Luke, 1772-1864.
Date:
1833
Catalogue details

Licence: Public Domain Mark

Credit: The climate of London, deduced from meteorological observations, made in the Metropolis, and at various places around it / by Luke Howard. Source: Wellcome Collection.

    28/458 (page 8)
    and larger, moderately loaded Ball, mounted on the centre of the vane, and turning with it. There are vanes to be had ready-made in London, which fulfil pretty nearly these conditions, that of great durability excepted. This is best insured, where expense is not an object, by using copper well gilt for the material. 3. As to positio)i: it is obvious that this instrument ought to be clear of deflections and eddies, from objects on the same or a higher level.* That it may the more easily be so placed, the spindle may end in a taper shaft, capable of receiving a fir pole : the latter should be well painted before fixing, and the Vane put on and adjusted after it is fixed. In this stage of the business the workman will require a Com¬ pass, if letters are as usual attached to the vane; and he must observe, that when the Needle, by moving the compass round, is made to point to the Variation north (at present 24° West of North), the north on the card of the compass will be the point for the north of the vane. The exact Variation is now annually inserted in the Philosophical Transactions, and other publica¬ tions. The vane in the figure is on the scale of an inch to a foot: the Section, in which the spindle, the Hint, and the guides are represented, is drawn two inches to the foot: the spindle and tube are stout enough for a much larger vane: the branches car¬ rying the ball are seen edgewise. OF THE BAROMETER. On the construction and uses of this instrument much has been written which need not be here repeated. In applying it to the purpose of the Meteorologist, it is the due attention of * The site of Geneva remarkably exemplifies the effect oflocal position in this respect. Here, owing to the direction of the valley, the vanes point almost constantly either to SM or NE: the cross winds going over above their level.