11M 



METEOROLOGY. 



[BEDUCIMO ODSRRVAI 



find the mean temperature of the dew-point, tlio 

 mean dry bulb* being 36 - , and the inuan wet bulb 

 34-6. 



Example L In the hygron>t r >'' : > 1 *-hlo f r 35- 

 The dew-point oppoeite to 34 wet 



Lull., is 32-4- 32-4 



The (low-point opposite to 36 wet 

 bulb, is 35-0 



Difference on the increase in dew- 

 point for mi increase of liu w> 

 Proportional part of iucn-a.sc for 0'5, is 



TfiiijH-nituro of tho dew-point corre- 

 sponding to 35 dry, and 34-5 wet, is 



In the fourth column, the decrease of 

 <!.- --point for an increase of 1" in 

 the dry bulb, is 1-6 ; the propor- 

 tional part for 0'8, is . 



+ 1-3 



337 



1-2 



The adopted temperature of tlie dew- 



for 35-tt dry, and 34-6 wet, is =02-3 



/' , nn/'l 2. To find the mean temperature of the dew- 

 point for the month of December, 1855, dry bulb being 

 3C-0", and wet bulb 34 5". 



In the livjjronietrical table for 30, 

 The dew-point opposite to 34' wet 



bulb, is ... . . 31-0- 31-0 

 The dew-point opposite to 35 wet 

 bulb, is ..... 33-5 



Difference ..... 2'5 

 l'i .portionnl part of tho increase) 



for 0-5, is ..... +1-2 



Mean temperature of dew-point 



322 



The same tables, and the same manner of reduction, 

 will tinil "the clastic force of vapour," " the weight of 

 vapour in a cubic foot of air," " the additional weight 

 required to saturate a cubic foot of air," and the "degree 

 of humidity." To render the tables clear, one example 

 of- each will bo worked out for a temperature of 35'8 

 dry bulb, and 34 5 wet bulb. 



To find the elastic force of vapour of the temperature 

 of 35-8, the wet bulb being 34-5. 



In the hygroinetrical table for 35, 



Inch. Incb. 



The elastic force of vapour oppo- 

 site to 34 wet bulb, is . . 0-184- . 0-184 



The elastic force of vapour oppo- 

 site to 35 wet bulb, is . . 0-204 



Difference, or the increase for an 



increase of 1 in wet . . 0'020 

 Proportional part of the increase for 0-5, is +0-010 



Elastic force of vapour corresponding to 

 35 dry, and 35-5 wet, is ... 0-194 



In tin- (ith column, the decrease of the elas- 

 tic force of vapour, for an increase of 1 

 in the ilry bulb, is O'OIO; the propor- 

 tional part for 0-8, in . . 



Mean elastic force of vapour 



0-008 

 =0-18C 



To find the whole amount of water in a vortical column 

 of the atmosphere i. r., from the surface of the earth to 

 the top of the atmosphere. 



Thin ii found by multiplying the elastic force of vapour 

 by the constant 1383, which would give, in this instant <, 

 for the whole amount of water in a vertical column of the 

 phi-re, if precipitated on tho earth at one time, a 

 of 2J inches. 



The bnnrlr mdlnr* f thi- thormnmrtrr, which im- made it the same 

 Haw tf tbow ul OH wet bulb, ire called the. "dry bulb." 



To find the weight of vapour in a cubic foot of air. 

 In tliu hygroiuutrical table of . 



Gralci. Ci:iins. 



The weight of vapour in a cubic 

 of air, oj ; wet 



bulb, is 21- . . 21 



Tho weight of vapour in a cubic 

 font of air opposite 3.V wut 

 bulb, is 2-t 



Difference, or tho increase in 

 weight of vapour for an in- 

 crease of 1 in wet, is . .03 



Proportional part of the increase 

 for05 a 



'it of vapour in a cubic foot of air cor- 

 responding to 35 J dry and 34-5 wet, is 

 In the 8th column, the docrea< of weight 

 of vapour for an increase of 1 in the dry 

 bulb, is 0'2 ; tho proportional part for 



+ 01 



0-8, is 



The adopted weight of vapour for 35-8 

 dry, and 34 '5 J wot, is . 



-0-2 

 20 



To find tho additional weight of vapour required to 

 saturate a cubic foot of air. 



In the hygrometrical table for 35, 



The dry bulb being 35-8, and the wet bu'b 34 5. 



Additional weight of vapour required 



to saturate a cubic foot of air oppo- Gn!n. Ovn. 

 Rite 34 wet bulb, is . . . 03-. 0'3 



Additional weight of vapour requin-.t 

 to saturate a cubic foot of air oppo- 

 site 35 wet bulb, is . . . O'O 



Difference, or the decrease in amount 

 required to saturate a cubic foot of 

 air for an increase in 1 in wet bulb, is 0'3 



Proportional part of tho decrease for 

 3-6 -02 



Additional weight of vapour required '.,> 

 saturate a cubic foot of air corresponding 

 to 35 dry and 34 '5 wet, is . . . = O'l 



In the 10th column, the increase in tin- weight 

 of vapour required to saturate a cubic foot 

 of air for .111 increase in 1 dry, is + 0'3 ; 

 tho proportional part for 8 D , is . . + 0'2 



Tho adopted additional weight of vapour re- 

 quired to saturate a cubic foot of air for 

 35 8 dry and 3-45 wet, is . . . . = 0'3 



To find tho decree of humidity, tho temperature 1 

 35 S and tho wet bulb 34 -5, complete saturation = 100. 

 In the hygroniotrical table for 35. 

 Degree of humidity opposite 34 wet 



bulb, is 90- . 93 



Degree of humidity opposite 35 wet 

 bulb, is 109 



Difference, or the increase of humi- 

 dity for an increase of 1 in wet, ia 



Proportional part of the increase for 

 5, is 



10 



+ 5 



95 



Degree of humidity corresponding to 35 dry 

 and 34-5 wet, is ..... 



In tlio 12th column, the increase in the degree 

 of humidity for an increase of 1 in the dry 

 bulb, is 9 ; the proportional part for 08, is 7 



oj.c. degree of humidity for 35-8 '!ry 

 and 315 wet, is ..... =83 



