148
MEDICAL TOPOGRAPHY OF MALVERN,
- ↑ The tables referred to above, will be found in Daniell's Meteorological Essays, second edition, viz.: that for the expansion of mercury, and the mean dilatation of glass, p. 372; table of expansion of air for temperature and vapour, p. 177; table of increase of density of air for vapour, p. 177.
Preliminary observations made with the same barometer, at both stations, May 30th, 1834.—First series.
Library House or Lower station. | Baro. | Attach. Therm. | Detach. Therm. | Hyg. | Time. (p. m.) |
Wind | Weather. |
Setting out | 29.705 | 65.0 | 61.0 | 55.0 | 5 30 | Light E. | Very fine, some detached clouds moving from N. W. |
Return | 29.700 | 63.0 | 57.0 | 52.0 | 7 20 | Ditto | |
Mean | 29.7025 | 64.0 | 59.0 | 53.5 | 6 25 | ||
Summit of the beacon | 28.700 | 53.0 | 53.0 | 48.0 | 6 45 | Very high E. | Less cloud, otherwise as above |
8. As this correct specific gravity is to 1.00000 (the standard) so is the approximate height (3) to the correct height.[1]
Details of the above formula, taking the second series of observations as data.
1. Mean of barometer at lower station. | 29.543 | Barometer at the upper station | 28.550 |
2. Subtract for the expansion of mercury at 65°. | —.083 | Subtract for expansion of mercury at 58° | .057 |
——— | ——— | ||
29.460 | 28.493 |
Logarithm. | ||||||
3. | 29.460 | 4692.321 | — Difference, | 144.945 | fathoms. | |
28.493 | 4547.3826 | 6 | ||||
———— | ||||||
Approximate height in feet | 869.670 |
4. | Lower station, temperature of the air | 65.0 | Dew-point | 58.5 |
Upper ditto, ditto | 58.0 | Ditto | 52.0 | |
—— | ||||
Mean | 61.5 |
Expansion of air for temperature | 61° (per table) | .06041 | |
5. | Ditto for vapour | 58° (ditto) | .01633 |
Ditto ditto | 52° (ditto) | .01336 | |
Mean | .01484 | ||
—— | |||
Total expansion | .07525 |
6. | Then, 1.07525 : 1.00000 : : 1.0000 | .93002 | |
7. | Increase of density of air for vapour at | 58°—.01051 | |
Ditto | 52°—.00864 | ||
Mean | .00958 | ||
——— | |||
Correct specific gravity of the air | .93960 | ||
8. | And, .93960 : 1.0000 : : 1.00000 : 925.5 the height in feet. |