Morning journal and courier., 1883-03-10
STORMS.


 hension for the burst of the mighty tempest which Professor Wiggins has been so long preparing, 1t paay perhaps beguiie the hours of suspense toIeara something of the man ner in which the great weather clerk at Wash 1 ington brews those little storms which ordi- l narily visit us. While the Canadian prophet pretends to get his knowledge of coming cy- clones from the stars, ''Old Probabilities is content with what little information he can pick up on earth. Wiggins despises this secondhand science, and claims that the sun and the planets too produce terrestrial storms, and, looking to these heavenly bodies, assumes to predict, far in advance of it's actu- al occurrence, what they have determined On the other hand ''O1d Prob.'' prefers not to tell us that storm is coming until he knows it has started. It will not do for him to lay weather embargo on all the shipping of the country based merely upon an nstro- nomical speculation. His data are we'll rec ognized facts.
 In 8 rough and general way his method may be described as follows: Storms are occasioned by inequalities in aerial pressure. The altitude of the atmosphere is temporari- ly greater in some places than in others. We hear of the approach of ''hot or cold wave. This figure of speech is 8 reality. There are waves in the air just as there are in the ocean. The atmosphere, like water, tends to a level, but much more rapidly as it is more mobile. There is 8 rush of air into the areas of low pressure from the areas of high press ure around it where the atmosphere is weighed down by the superior altitude. The air is warmest as everybody knows, nearest the earth's surface. The earth absorbs about three-fourths of the suns heat Thus the atmosphere receives its heat in it's lowest and loses it from it's highest stratum. The warm air rushing in from the area of high pressure is forced upwards in the area of low pressure, and when it reaches height of about two miles its moisture is condensed by the cold and is returned in the form of rain or snow according to the temperature. Thus it is that storm always covers an area of low pressure. Hence 1t is, too, that the wind always blows towards 8 storm from all directions around it. In this part of the country there is an old fashioned notion that east winds produce rain because they bring clouds which are formed by evaporation from the ocean. This is an error Storms move from westerly towards an easterly direction and never from east to west. An east wind simply indicates that storm is coming from the west, to- wards which the wind is blowing. When the storm has arrived and passed beyond us the wind then blows from westerly quarter. Hence it happens that on this coast east winds precede and west winds follow a storm.
 But to return to our weather clerk. How does he know where the storm area is There are 11S signal stations scattered over the country. Their locations are generally chosen for their meteorological rather than their commercial importance. It is, however, necessary 10 have them in the most important ports for the sake of the shipping interests. At all the signal stations observations are made five times day-at and II g. m, 3. and Il p. m From the observations taken at 8. m., and Il D. m. the weather indi- cations are made up and autographed to Wash ington. These reports contain statement of the height of the mercury in the baronne-- ter and thermometer, the direction and ve- locity of the wind, the humidity of the at-
 
 mosphere, the amount of elcudiness and the character of the clouds and also the amount of rain or snow, if any, that has fallen since the last observation. ..Old Prob. 2 has upon his desk large outline map and he enters upon the places that represent the several signal stations the results of their respective observations He draws lines called .'isobars" through the places where the pressure as indicated by the barometer is the same. The lowest barometer is always found at the storm center. A series of successive ssisobarsn drawn at every tenth of increase in barometer from high to low pressure, fol lowing much the same course, mark the re- eions of fair weather and of storms, and show the meteorological condition of the country. A weather map ssored by these lines is daily issued by the Nureau. copy of which can be seen at any signal station. Ex- perienes has established that the storm