270 



Abstracts of the Makerstoun Observations, 1843. 



P 



TABLE IX. — Daily, Weekly, and Monthly Means of the Pressure of Aqueous Vapour in inches of 



Mercury, as deduced from Tables I. and VII. 



("ivil J 

 Day. 



an. F 



eb. Me 



irch. 



April. May. June. July- Aug. Sept. Oct. Nov. Dec. 





m. 



in. 



in. 



in. 



in. 



in. 



in. 



in. 



in. 



in. 



in. 



in. 



1 [• 



] 



221 



162 



0-322 > 



264 



326 



374 



403 



483 [0 



324] 



193 



191 



2 



154 



183 



167 



[ -275] 



256 



355 [ 



371] 



410 



529 



300 



236 



254 



3 



170 



166 



166 



•272 



281 



278 



404 



414 [ 



423] 



337 



232 [ 



257] 



4 



197 



173 



157 



•279 



286 [ 



306] 



346 



417 



319 



396 



296 



321 



5 



163 [ 



200] [ 



184] 



•253 



225 



253 



471 



344 



338 



386 [ 



245] 



268 



6 



211 



178 



244 



•269 



247 



301 



396 [ 



413] 



481 



417 



280 



227 



7 



220 



241 



210 



•267 [ 



258] 



322 



384 



423 



366 



359 



250 



310 



8 [ 



191] 



259 



163 



•228 



257 



333 



395 



498 



394 [ 



331] 



177 



261 



9 



204 



195 



184 



[ ^205] 



278 



334 [ 



387] 



383 



419 



275 



174 



306 



10 



177 



178 



210 



•150 



255 



322 



384 



361 [ 



423] 



275 



245 [ 



293] 



11 



174 



177 



258 



•151 



265 [ 



327] 



•351 



426 



504 



272 



■281 



294 



12 



141 [ 



164] [ 



210] 



•166 



301 



296 



•414 



453 



493 



202 [ 



227] 



299 



13 



202 



172 



206 



•165 



357 



312 



431 [ 



432] 



365 



178 



241 



290 



14 



156 



134 



201 



•288 [ 



294] 



365 



393 



394 



385 



184 



197 



296 



15 [ 



202] 



125 



199 



•282 



300 



354 



398 



458 



437 [ 



186] 



224 



283 



16 



192 



135 



225 



[ ^270] 



294 



333 [ 



396] 



504 



418 



167 



212 



217 



17 



229 



143 



284 



•291 



249 



327 



408 



541 [ 



408] 



207 



273 [ 



273] 



18 



293 



107 



297 



•280 



228 [ 



333] 



•401 



501 



428 



180 



215 



285 



19 



294 [ 



166] [ 



275] 



•317 



217 



303 



345 



499 



342 



177 [ 



243] 



260 



20 



238 



167 



249 



•271 



260 



323 



342 [ 



431] 



438 



285 



246 



•298 



21 



174 



218 



294 



•320 [ 



273] 



361 



337 



329 



392 



271 



271 



260 



22 [ 



250] 



228 



304 



•315 



304 



319 



397 



390 



356 [ 



245] 



•239 



308 



23 



243 



223 



303 



[ ^265] 



324 



360 [ 



375] 



324 



380 



•289 



•222 



323 



24 



281 



223 



261 



•238 



306 



348 



308 



335 [ 



312] 



238 



■186 [ 



299] 



25 



273 



196 



223 



•239 



331 [ 



317] 



379 



383 



282 



208 



186 



331 



26 



263 [ 



194] [ 



220] 



•207 



359 



322 



489 



389 



229 



179 [ 



237] 



294 



27 



342 



181 



182 



•235 



328 



296 



357 [ 



363] 



231 



185 



311 



279 



28 



224 



182 



174 



•264 [ 



307] 



256 



385 



423 



233 



264 



295 



281 



29 [ • 



259] 





176 



•261 



241 



298 



399 



331 



262 [ 



202] 



220 



277 



30 



217 





224 



[ -260] 



277 



334 [ 



386] 



320 



418 



198 



283 



258 



31 



286 





299 





308 





365 



390 





196 



[ 



220] 



Mean 



220 



184 



223 



0^253 0^281 0-320 ! 0^387 0^409 0-382 0-245 0^238 0-280 



The quantities in Table IX. have been deduced from Tables I. and VII. by means of Dr Apjohn's for- 

 mula, taken approximately, namely (Proceedings of the Koyal Irish Academy, 1840), 



d 29-7 



/"=/' 



X 5777:, the temperature of evaporation being above 32° 



88 30-0 



d 



below 32° 



.„_.,_ ^ 297 

 ^ ~-' 96 ^ 30-0' 



Where/" is the tension of aqueous vapour in the air, given in the previous Table ; /', the tension of aqueous 

 vapour, the air being saturated at the temperature of evaporation ; d, the difference between the temperatures 

 of the air and of evaporation; 29'7, the mean barometric pressure. The values of/' were obtained from 

 the Table, page xl.. Introduction to the Greenwich Observations, 1842. The errors for the monthly or hourly 

 means, from the use of the approximate formula, are small, the greatest error is probably under 0-003 in. The 

 errors of the daily means will be due chiefly to the want of the three two-hourly observations. 



The Annual Variation of the Pressure of Aqueous Vapour follows the same march as the temperature of 

 the air. The greatest monthly mean is that for August, and the least that for February ; the former being 

 0*409 in., the latter being 0-184 in., and the annual range of the monthly means 0-225 in. The means for 

 the mean meteorological seasons, and the meteorological seasons /or the year 1843, are — 



in. in. 



Spring, Mar., Apr., May, 0-252 Apr., May, June, 0-285 



Summer, June, July, Aug., 0-372 July, Aug., Sept., 0-393 



Autumn, Sept., Oct., Nov., 0-288 Oct., Nov., Dec, 0-254 



Winter, Dec, Jan., Feb., 0-228 Jan., Feb., Mar., 0-209 



The year 1843, 0-283 inch. 



