620 Abstract of a Meteorclogical Register [Dxc. 
Table of the mean Monthly and Diurnal Range of the Barometer and Thermome- 
ter at Kotgarh in 1819—20, (the month April being interpolated,) deduced from 
Captain Gerard's journals. 
} Barometer. | raES: Thermometer, 
A. - = Ge D. | E. We “ G. 53 H. 
eviati le, 
Month. Wear from mean Fes) Mean of ; Mean of fenie: vom tea Mean 
height. annual |). .j]}q- |Minimain|maximain} rature} annual diurnal 
height. oie | the open doors. in tempera- | range 
air. doors. ture. (e.—d.) 
in in in | Co) 0 0 ta) o 
January,.. | 23.592 —.001| 0.052| 33.4 40.9 39.5 —20.4 7.5 
February, 632 +.039} .052| 35.3 45.0 43.5 —13.4 9.7 
March, ... 686 +.093! .062| 43.5 52.2 51.4 — 5.5 8.7 
April, ....] 623 +.040| .067| 47. 58. 57. + 0.1 | 11.0 
May,..... 559 —.034| .074| 52.4 64.7 63 4 + 65 | 123 
June,.... 461 —.132| .068) 60.5 72.1 69.8 | +12.9 | 11.6 
Jtaliymtensse 495 —.098; .061 | 69.8 71.4 69.3. +12.4 | 10.6 
August,... 501 —.092) .062! 60.6 71.4 69.6 +127 | 10.8 
September,| 522 —.071} .058) 542 69.3 66.7 + 9.8 | 15.1 
October,..|  .639 +.046| .072} 48.9 625 | 597 | + 28 | 13.4 
November, 693 +.100; .063; 37.2 49.5 48.3 — 8.6 | 123 
December, 711 +.118} .064) 39.3 46.6 45.0 —I119 | 13.3 
Mean, ....| 23.593 jrange .250 063) 47.7 58.6 56.9 |range 33.3] 11.3 
In the column (c) of mean diurnal barometric oscillation, the ob- 
servations at Subatha have been included, as producing a better average ; 
the difference of altitude will in this case have but a trifling influence 
on the result. 
Appended to Captain P. Gerard’s tables are catalogues of the lati- 
tude, longitude, and barometrical altitude of all the most important 
‘ points visited in the course of the journeys, whose occurrence is mark- 
ed by the blanks in the foregoing register. The journey of Septem- 
ber, 1819, was made in company with the late Captain J. D. Hersurr, 
to survey the course and level of the river Sat/ej, of which an interesting 
account is published in the fifteenth volume of the Asiatic Researches. 
The heights were partly taken trigonometrically, but the majority by the 
boiling-point method, anda correction of two degrees and upwards was 
forced to be applied to the instrument used by Captain Herserr, on 
account of an error deduced experimentally from a comparison of its 
boiling point with the height of a barometer filled with pure mercury, 
and well boiled, by Captain Grrarp; Datron’s Table of Tensions 
were used in calculating the volume of the thermometric indications. 
The latter officer, in his remarks upon the tables before us, explains 
that his own thermometrical heights were taken with a differ- 
ent instrument, which did not require correction, and that they 
were calculated by his brother, Captain A. Gzrarp, on the supposi- 
tion of the sea level being represented by 30 inches, or 212°. A de- 
duction of 200 feet may in some cases be necessary on this account, 
but it will hardly affect the relative measurements, especially as the 
