Mr. Strachan, in his able pamphlet on “Weather Forecasts,” puts the matter thus: “It follows from Ballot’s Law that in the northern temperate zone the winds will circulate around an area of low atmospherical pressure in the _reverse direction_ to the movement of the hands of a watch, and that the air will flow away from a region of high pressure, and cause an apparent circulation of the winds around it, _in the direction_ of watch hands.” And as the result of a careful digest of data contained in the eleventh number of meteorological papers, published by the Board of Trade, he has established the following valuable propositions. As introductory to the propositions, it should be stated that the positions of observations were the following:— Places. Latitude. Longitude. Nairn 57° 29´ N. 4° 13´ W. Brest 48 „ 28 4 „ 29 W. Valentia 51 „ 56 10 „ 19 W. Yarmouth 52 „ 37 1 „ 44 E. Portrush (or Greencastle) 55 „ 12 6 „ 40 W. Shields 55 „ 0 1 „ 27 W. Nairn and Brest are situated nearly on the same meridian, about 540 geographical miles apart. Valentia and Yarmouth are nearly on the same parallel of latitude, about 450 miles apart. Portrush and Shields, distant 180 miles, are on a parallel which is nearly as remote from the parallel of Nairn as that of Valentia and Yarmouth is from the one passing through Brest; and Shields is about as much to the westward of Yarmouth as Portrush is to the eastward of Valentia. When observations have not been obtainable for Brest, those made at Penzance have been used instead. _Proposition 1._—Whenever the atmospherical pressure is greater at Brest than at Nairn, while it is of the same or nearly the same value at Valentia and Yarmouth, being gradually less from south to north, the winds over the British Isles are _westerly_. _Proposition 2._—Whenever the pressure at Nairn is greater than at Brest, while its values at Valentia and Yarmouth are equal, or nearly so, the winds over the British Isles are _easterly_. _Proposition 3._—Whenever the pressure at Valentia is greater than at Yarmouth, while its values at Brest and Nairn are nearly equal, the winds over the British Isles are _northerly_. _Proposition 4._—Whenever the pressure at Yarmouth exceeds that at Valentia, while there is equality of pressure at Nairn and Brest, the winds of the British Isles are _southerly_. _Proposition 5._—Whenever the pressure of the atmosphere is equal, or nearly so, at Brest, Valentia, Nairn, and Yarmouth, and generally uniform, the winds over the British Isles are variable in direction and light in force. The data from which the foregoing propositions were deduced, and indeed all other cases calculated by Mr. Strachan, show in every well marked instance that when the atmospherical pressure was