occurs arises solely from the high summer temperature. It is to the centre of Asia we must look for an example of this; and accordingly the pressure of the dry air at Barnaul, in Siberia, on a mean of ten years, is 29.760 inches in January, and 28.666 inches in July,-thus showing the enormous difference of nearly eleven tenths of an inch. 687. This question has important bearings on storms, particularly on the storms of Great Britain, which is situated within the southern limits of the region of most anomalous barometric pressure, which has its centre in Iceland. As the summer temperature falls in September and October the pressure is increased over the continents of Asia, Europe, and North America, and consequently air-currents are poured into the northern part of the Atlantic, in larger volume and with accelerated velocity; and since at the same time the temperature is everywhere falling, the whole atmosphere becomes saturated with vapour. This accumulated vapour is discharged in those furious storms of wind and rain which strew our shores with wrecks, and carry misery and desolation into the hearths of our seafaring population. Considering the important interests at stake, no amount of labour and no expense can be regarded as too great which might lead to a better understanding of these great atmospheric disturbances. N 88 .047 .048 .049 .050 .051 47 .050 .051 .054 .055 .056 .059 .065 .066 53 75 80 81 82 .134 .136 .139 .139 .141 .144 86 89 .141 TABLE II.-FOR CONVERTING MILLIMETRES INTO ENGLISH INCHES AND DECIMALS. 661 26.024 687 27.048 713 28.071 739 29.095 765 30.119 662 26.063 688 27.087 714 28.111 740 29.134 766 30.158 666 26.221 692 27.245 718 28.268 744 28-308 745 29.174 767 30.197 29.213 768 30.237 29.252 769 30.276 29.292 770 30.316 29.331 771 30.355 29.371 772 30.394 28.386 747 29.410 773 30.434 28.426 748 29.449 774 30.473 29.489 775 30.512 28.504 750 29.528 776 30.552 29.567 777 30.591 685 26.969 711 27.993 737 29.016 763 686 27.008 712 28.032 738 29.056 764 30.079 790 31.103 28.938 761 29.961 787 30.985 31.024 0 TENTHS OF A MILLIMETRE IN THE DECIMAL OF AN INCH. 1 2 3 4 5 6 7 8 9 0.000 0.004 0.008 0.012 0.016 0.020 0.024 0.028 0.031 0.035 TABLE III.-FOR CONVERTING FRENCH OR PARIS LINES INTO ENGLISH INCHES. A Paris Line equals 0.088814 English Inch. Paris Lines. English Paris English. Paris English Paris English Paris English 26.733 26.644 312.0 27.710 26.777 26.822 27.177 294.5 26.156 306.5 27.221 295.0 26.200 307.0 27.266 295.5 26.245 307.5 27.310 296.0 26.289 308.0 27.355 320 0 288.0 25.578 300.0 324.0 288.5 25.623 300.5 324.5 28.820 336.5 289.0 25.667 301.0 325.0 28.865 337.0 289.5 25.712 301.5 313.5 27.843 325.5 28.909 290.0 25.756 302.0 314.0 27.888 326.0 28.953 290.5 25.800 302.5 26.866 314.5 27.932 326.5 28.998 291.0 25.845 303.0 26.911 315.0 27.976 327.0 29.042 339.0 30.108 291.5 25.889 303.5 26.955 315.5 28.021 327.5 29.087 339.5 292.0 25.934 304.0 26.999 316.0 28.065 328.0 29.131 340.0 292.5 25.978 304.5 27.044 316.5 28.110 328.5 29.175 340.5 293.0 26.023 305.0 27.088 317.0 28.154 329.0 29.220 293.5 26.067 305.5 27.133 317.5 28.198 329.5 29.264 341.5 30.330 294.0 26.111 306.0 318.0 28.243 330.0 29.309 342.0 30.374 318.5 28.287 330.5 29.353 342.5 30.419 819.0 28.332 331.0 29.397 343.0 30.463 319.5 28.376 331.5 29.442 343.5 30.50S 28.420 332.0 29.486 344.0 30.552 28.776 336.0 29.842 29.886 29.930 TABLE IV.-FOR REDUCING BAROMETRIC OBSERVATIONS TO THE LEVEL OF THE SEA; AND CONVERSELY, FOR THE DETERMINATION OF HEIGHTS BY THE BAROMETER. 110 .135 .132 .129 120 .148 .144 .141 130 .160 .156 140 .172 200 .124 .121 .138 .135 .132 .153 .149 .146 .143 .168 .164 .160 .157 .154 .150 150 .184 .179 .175 .171 .168 .165 .160 .157 160 .196 .191 .187 .183 .179 .175 .171 .168 170 .208 .203 .198 .194 .190 .186 180 .220 .215 .200 .206 .201 .197 190 .232 .227 .222 .217 .212 .208 .203 .199 .244 .238 .233 .228 .223 .218 .213 .209 .126 .118 .116 .126 .124 .121 .004 .139 .137 .147 .144 310 .377 .368 .360 .352 .344 .337 .329 320 .389 .380 .372 .363 .355 .348 .340 .333 .326 .320 330 .401 .391 .383 .374 .366 .358 .350 .343 .336 .329 .012 340 .413 .403 .394 .385 .377 .369 .361 .354 .346 .339 .012 350 .425 .415 .406 .397 .388 .380 .371 .364 .356 .349 .013 360 .438 .427 .417 .408 .399 .390 .382 .374 .366 .859 .013 370 .450 .439 .429 .419 .410 .392 .384 .376 380 .462 .451 .440 .430 390 .474 .463 400 .486 .475 410 .498 .487 .475 .464 .454 .444 .434 420 .510 .498 .486 .475 .465 .455 .444 .435 430 .522 .509 .497 .486 .476 .465 .455 .446 440 .534 .521 .509 .497 .487 .476 .465 .456 .447 .437 .016 450 .546 .532 .520 .508 .498 .487 .476 .466 .457 .447 .016 460 .558 .544 .532 .520 .509 .498 .486 .477 .467 .457 .017 470 .570 .556 .543 .531 .520 .508 .497 .487 .477 .467 .017 480 .581 .568 .555 .542 .530 .519 .507 .497 .487 .477 .018 490 .593 .579 .566 .553 .541 .529 .518 .507 .497 .486 .018 500 .605 .591 .577 .564 .551 .539 .528 .517 .507 .496 .018 |