Abstract of a Meteorological Journal Kept at Benares during the Years 1824, 1825, and 1826

XI. Abstract of a meteorological journal kept at Benares during the years 1824, 1825, and 1826. By James Prinsep, Esq. Assay Master of the mint at Benares. Communicated by Peter Mark Roget, M.D. Secretary of the Royal Society. Read January 25, 1828. The three principal Tables, each of which comprises the abstract for one year of the meteorological journal at Benares, are followed by two others, numbered I. and II., presenting the mean daily oscillations of the barometer, and the monthly deviations from its average height, for each month during four successive years, accompanied by the corresponding variations of the thermometer from its mean. These tables exhibit the remarkable coincidence preserved by these phenomena throughout the year. The indications of the barometer are all reduced to the freezing point by Dulong and Petit's formula for the dilatation of mercury. I have inserted in the first column of Table I. the mean of three years' observations made at Berhampoor by Dr. A. Russel; but the instrument employed being of the mountain construction, the mercury did not move freely in the tube, which will account for the oscillations being uniformly less than those measured by myself. Mr. Daniell has noticed the liability of barometers to deteriorate from the accumulation of air bubbles above the mercury: to obviate this cause of error, I made frequent comparisons with one of Wollaston's boiling thermometers. From October 1823 to August 1825, the error from this cause amounted to .046 inch, and I deemed it necessary to reboil the barometer; it then stood, as nearly as possible, correct once more. All of my tables have been cleared of the minute error thus found. As a graphic representation more readily enables the eye to estimate the agreement of two lines in motion, I have delineated in a diagram the courses indicated by Table II., only reversing the direction of one curve, that the two lines may be collateral with respect to the centre line which stands for the annual mean. The scales at the sides will explain the formation of the curves. The year 1826 is omitted in the diagram, because the last two months are wanting in the series of observations. ## Abstract of a Meteorological Journal: Benares, 1824. | Date | Barometer | Thermometer | Wet Bulb Therm* | Hair Hygrometer | Evaporation | Rain | Wind | Weather | |----------|-----------|-------------|-----------------|-----------------|-------------|------|------|--------------------------| | | Obs. | Mean | Interior | Exterior | Extremes | Mean | Diff. +0.8 | | | Jan. 9 | 29.892 | 29.849 | 59.82 | 61.08 | 57.32 | 49.68| 56.60 | One shower | | | 29.807 | | 62.35 | | 63.27 | 69.35| 59.52 | W. and Calm. Foggy: clear: change. | | Feb. 10 | 29.786 | 29.737 | 66.40 | 68.26 | 68.16 | 55.40| 61.34 | W. and Calm. Cirrocum. Hard winds. | | | 29.688 | | 70.12 | | 67.32 | 76.52| 65.96 | | | March 10 | 29.752 | 29.701 | 75.70 | 77.96 | 79.42 | 66.30| 67.32 | W. Several gales. | | | 29.650 | | 80.22 | | 83.40 | 86.11| 76.20 | | | April 10 | 29.659 | 29.601 | 82.85 | 84.87 | 85.42 | 73.75| 84.42 | W. Steady weather. | | | 29.544 | | 86.89 | | 92.38 | 95.10| 70.84 | | | May 10 | 29.500 | 29.442 | 88.59 | 90.32 | 95.12 | 80.97| 74.38 | N.W. Clear: then misty: then gale and violent storm. (Sultan-poor barracks blown down.) | | | 29.385 | | 92.05 | | 99.66 | 97.39| 92.33 | | | June 10 | 29.387 | 29.330 | 89.11 | 90.78 | 89.76 | 77.11| 89.38 | W. Var. E: Little rain, but cloudy. | | | 29.274 | | 92.46 | | 89.42 | 89.59| 84.42 | | | July 11 | 29.322 | 29.287 | 85.65 | 86.43 | 85.79 | 80.18| 85.29 | E. W. S.W. E: Settled rain. | | | 29.253 | | 87.22 | | 85.95 | 90.40| 90.40 | | | August 10| 29.402 | 29.373 | 81.76 | 86.04 | 85.96 | 80.60| 85.30 | Calm. E. Var. Fine towards the 15th. | | | 29.344 | | 90.33 | | 85.15 | 85.55| 83.28 | | | Sept. 10 | 29.572 | 29.528 | 85.65 | 86.85 | 84.90 | 77.43| 84.38 | W. Var. E: Showers: clear: cloudy. | | | 29.484 | | 88.06 | | 86.94 | 85.92| 91.33 | | | Oct. 10 | 29.712 | 29.669 | 81.60 | 82.26 | 80.94 | 72.28| 79.12 | E. Calm. Var. A gale from W: then clear: then squally. | | | 29.627 | | 82.93 | | 81.15 | 81.04| 78.81 | | | Nov. 10 | 29.819 | 29.774 | 74.36 | 75.36 | 72.11 | 72.94| 59.68 | Var. Calm. Cleared up. | | | 29.729 | | 76.37 | | 73.78 | 72.94| 69.09 | | | Dec. 10 | 29.873 | 29.835 | 65.56 | 66.36 | 62.15 | 50.58| 59.04 | W. Var. S.E.: Clear and fine: gale on the 30th. | | | 29.797 | | 67.16 | | 64.49 | 63.32| 58.19 | | Annual Mean: 29.593, 79.71, 79.99, 77.50, 72.07, 87.04 * This thermometer stands 0.8 deg. higher than the others; this quantity is therefore added to the column of differences. | Date | Barometer | Thermometer | Wet Bulb Therm. | Hair Hygr. | Evaporation | Rain. | Wind. | Weather | |------------|-----------|-------------|-----------------|------------|-------------|-------|-------|---------| | Jan. | | | | | | | | | | 10 3/4 A.M.| 29.883 | 64.54 | 62.97 | 62.33 | 54.12 | 61.05 | 61.55 | 2.78 | | 5 P.M. | 29.797 | 66.15 | 65.35 | 64.09 | 68.14 | 62.06 | | | | Feb. | | | | | | | | | | 11 A.M. | 29.803 | 67.88 | 68.95 | 72.11 | 67.11 | 69.61 | | | | 4 1/2 P.M.| 29.732 | 70.02 | | | | | | | | March | | | | | | | | | | 10 1/2 A.M.| 29.785 | 74.53 | 74.29 | 75.96 | 75.09 | 63.68 | 65.02 | 65.51 | | 5 1/2 P.M.| 29.673 | 78.42 | | | | | | | | April | | | | | | | | | | 10 A.M. | 29.661 | 85.29 | 85.84 | 91.90 | 88.05 | 75.11 | 87.65 | 73.95 | | 5 1/4 P.M.| 29.550 | 86.39 | | | | | | | | May | | | | | | | | | | 10 A.M. | 29.595 | 89.10 | 89.82 | 96.14 | 93.39 | 94.76 | 81.79 | 93.61 | | 6 P.M. | 29.485 | 90.54 | | | | | | | | June | | | | | | | | | | 10 A.M. | 29.420 | 89.68 | 90.00 | 93.65 | 91.30 | 92.47 | 85.19 | 91.56 | | 6 1/4 P.M.| 29.311 | 90.32 | | | | | | | | July | | | | | | | | | | 10 1/2 A.M.| 29.404 | 87.03 | 87.83 | 86.91 | 85.82 | 86.36 | 82.29 | 82.47 | | 6 1/4 P.M.| 29.317 | 88.44 | | | | | | | | August | | | | | | | | | | 10 1/2 A.M.| 29.518 | 87.68 | 88.80 | 88.50 | 86.61 | 87.55 | 81.30 | 81.80 | | 6 P.M. | 29.425 | 89.92 | | | | | | | | Sept. | | | | | | | | | | 10 1/2 A.M.| 29.581 | 85.13 | 85.96 | 85.13 | 83.85 | 84.49 | 79.95 | 83.69 | | 6 P.M. | 29.468 | 86.79 | | | | | | | | Oct. | | | | | | | | | | 10 1/2 A.M.| 29.702 | 81.13 | 82.24 | 81.69 | 80.05 | 80.57 | 74.68 | 79.54 | | 5 1/2 P.M.| 29.615 | 83.35 | | | | | | | | Nov. | | | | | | | | | | 10 1/2 A.M.| 29.829 | 75.59 | 74.04 | 72.78 | 69.84 | 71.31 | 62.29 | 68.96 | | 5 1/2 P.M.| 29.718 | 75.48 | | | | | | | | Dec. | | | | | | | | | | Average | | 29.620 | 80.16 | 79.96 | | | | | **Notes:** - **Barometer:** Observations in inches. - **Thermometer:** Observations in degrees Fahrenheit. - **Wet Bulb Therm.:** Observations in degrees Fahrenheit. - **Hair Hygr.:** Observations in percent. - **Evaporation:** Observations in inches. - **Rain:** Observations in inches. - **Wind:** Observations in miles per hour. - **Weather:** Description of weather conditions. **Legend:** - Unseasonable strati-fogs; rain; storms; cumuli. - Clear; cirri. Severe heavy storms; then clear. - Dull haze; violent storm; clear. - Clear; cirostrati; hard gale E. Changeable. - Clear; gale from N. - Cloudy; hard gale E.; showers. - NE. Cloudy; hard gale W.; showers. - Calm. - Hot and cloudy. - Gale three days: cumul.; cirri.; fair. - Rain and gale: dry weather; clear. - Cloudless sky to the 18th; thenshowers. - Dry and colder than usual. | Date | Barometer: | Thermometer: | Wet Bulb Ther. | Hair Hygr. | Evaporation. | Rain. | Wind. | Weather. | |------------|------------|--------------|----------------|------------|--------------|-------|-------|----------| | | Obs. | Mean. | Extremes. | Obs. | Mean. | | | | | | | | | D.H. +O.S.| Mean. | | | | | Jan. | 10 1/2 A.M.| 29.835 | 64.85 | 61.34 | 53.57 | 73.4 | 71.6 | Clear and cold; one storm. | | | 5 1/2 P.M. | 29.787 | 68.91 | 66.88 | 61.64 | 69.72 | 60.8 | Calm. | | Feb. | 10 1/2 A.M.| 29.737 | 71.38 | 72.38 | 67.62 | 67.22 | 57.81 | Steady; clear. | | | 5 1/2 P.M. | 29.689 | 72.38 | 72.64 | 70.13 | 76.64 | 67.91 | Calm. | | March | 10 1/2 A.M.| 29.751 | 77.14 | 77.99 | 80.78 | 86.55 | 77.23 | Var. | | | 5 1/2 P.M. | 29.698 | 79.89 | 83.59 | 80.78 | 86.55 | 77.23 | Very dry on 31st. | | April | 10 A.M. | 29.625 | 83.55 | 87.31 | 89.99 | 92.52 | 87.31 | Steady not wind. | | | 6 P.M. | 29.558 | 84.69 | 89.31 | 90.83 | 94.83 | 89.02 | Several storms; D eclipsed 21st. | | May | 9 1/2 A.M. | 29.575 | 88.18 | 89.02 | 90.91 | 94.83 | 89.02 | Changeable; one gale. | | | 6 P.M. | 29.506 | 89.87 | 90.91 | 91.84 | 94.83 | 89.02 | Changeable; one gale. | | June | 9 1/2 A.M. | 29.406 | 88.64 | 89.91 | 87.72 | 89.91 | 89.91 | Var. | | | 6 1/2 P.M. | 29.355 | 89.18 | 89.85 | 88.78 | 89.61 | 89.61 | Var. | | July | 9 1/2 A.M. | 29.325 | 86.74 | 87.08 | 84.42 | 84.42 | 84.42 | Heavy rain. | | | 6 P.M. | 29.294 | 87.43 | 87.08 | 84.42 | 84.42 | 84.42 | Heavy rain. | | Aug. | 10 A.M. | 29.470 | 85.88 | 85.76 | 83.99 | 84.15 | 84.15 | Var. | | | 6 P.M. | 29.431 | 86.24 | 85.76 | 83.99 | 84.15 | 84.15 | Var. | | Sept. | 10 1/2 A.M.| 29.549 | 86.56 | 87.21 | 85.75 | 87.21 | 87.21 | Set in fine on the 16th. | | | 6 P.M. | 29.502 | 87.86 | 86.29 | 85.75 | 87.21 | 87.21 | Set in fine on the 16th. | | Oct. | 10 A.M. | 29.757 | 83.93 | 83.94 | 82.56 | 73.96 | 73.96 | Clear and fine; one squall 14th. | | | 6 P.M. | 29.650 | 86.27 | 86.27 | 83.94 | 83.94 | 83.94 | Clear and fine; one squall 14th. | ### Table I. Daily Oscillations. | Month | Barometer | Thermometer | |-------------|-----------|-------------| | | 3 Years by Dr. Russel | 1824. | 1825. | 1826. | Mean of last | 1823. | 1824. | 1825. | 1826. | Mean | | January | .073 | .092 | .091 | .109 | .097 | 21°.5 | 19°.7 | 14°.0 | 16°.1 | 17°.8 | | February | .098 | .109 | .096 | .103 | .103 | 21.0 | 21.1 | 16.1 | 18.8 | 19.2 | | March | .098 | .117 | .124 | .122 | .121 | 24.0 | 19.8 | 20.3 | 18.6 | 20.7 | | April | .103 | .127 | .113 | .135 | .125 | 26.5 | 21.3 | 25.1 | 19.9 | 23.2 | | May | .103 | .120 | .113 | .140 | .124 | 23.4 | 22.7 | 23.6 | 18.0 | 21.9 | | June | .084 | .119 | .111 | .109 | .113 | 20.3 | 24.5 | 11.7* | 7.9 | 16.1 | | July | .062 | .071 | .091 | .070 | .077 | 9.3 | 10.2 | 7.7 | 6.9 | 9.0 | | August | .068 | .084 | .099 | .082 | .088 | 8.9 | 9.4 | 8.6 | 6.3 | 8.3 | | September | .070 | .094 | .117 | .098 | .103 | 9.5 | 13.9 | 8.5 | 9.2 | 10.3 | | October | .070 | .103 | .094 | .102 | .100 | 16.0 | 13.7 | 9.7 | 13.2 | 18.1 | | November | .070 | .095 | .120 | — | .107 | 18.4 | 18.8 | 13.3 | — | 16.8 | | December | .075 | .085 | .111 | — | .098 | 15.7 | 17.9 | 15.4 | — | 16.3 | * From this month the Register Thermometer stood in a new house much less exposed than before;—the ranges are consequently much smaller. ### Table II. Monthly Deviations. | Month | Barometer at 32° | Thermometer (mean of extremes.) | |-------------|------------------|---------------------------------| | | 1823. | 1824. | 1825. | 1826. | Mean. | 1823. | 1824. | 1825. | 1826. | Mean | | January | +.285 | +.299 | +.277 | +.232 | +.273 | -16.7 | -18.0 | -17.0 | -16.5 | -17.0 | | February | +.233 | +.165 | +.184 | +.119 | +.175 | -10.7 | -11.5 | -13.1 | -10.9 | -11.5 | | March | +.095 | +.106 | +.124 | +.104 | +.107 | + 0.5 | - 1.3 | - 4.3 | - 0.9 | - 1.5 | | April | -.083 | -.016 | -.027 | -.048 | -.043 | +11.2 | + 6.9 | + 9.5 | +10.3 | + 9.5 | | May | -.137 | -.192 | -.104 | -.113 | -.136 | +12.7 | +14.8 | +15.5 | +12.7 | +13.9 | | June | -.307 | -.304 | -.278 | -.267 | -.289 | +15.7 | +11.9 | +13.4 | +11.5 | +13.1 | | July | -.311 | -.327 | -.277 | -.318 | -.308 | + 6.1 | + 7.8 | + 7.6 | + 6.1 | + 6.9 | | August | -.227 | -.242 | -.168 | -.175 | -.203 | + 5.0 | + 7.8 | + 7.9 | + 5.1 | + 6.4 | | September | -.130 | -.041 | -.108 | -.111 | -.098 | + 4.5 | + 6.9 | + 5.6 | + 6.3 | + 5.8 | | October | +.084 | +.066 | +.036 | +.099 | +.074 | - 0.1 | + 1.6 | + 1.4 | + 2.5 | + 1.3 | | November | +.169 | +.201 | +.175 | — | +.181 | -11.3 | - 8.5 | - 9.2 | — | - 9.7 | | December | +.309 | +.290 | +.240 | — | +.279 | -17.0 | -18.5 | -17.4 | — | -17.6 | Mean Barometric Alt. 29°.468. Mean Thermometric Alt. 77°.81.