72 Transactions. — Miscellaneous. 



be more correct, as, although these clouds, as seen generally 

 rather low down in the eastern sky, seem like fishes with 

 smooth hog backs, yet no doubt they w^ould present some- 

 what the same appearance if viewed sideways from any other 

 point. 



The peculiarity of these clouds is that they are very smooth 

 and regular in their upper curved surfaces, and comparatively 

 fiat below — quite diflerent from the bubbling surface of a 

 cumulus cloud, or from the straightly-drawn-out forms of 

 stratus clouds, and also widely differing from the delicate 

 feathery forms of the high cirrus clouds. 



The fish clouds belong to the class cirrostratus generally, 

 and I should estimate that their normal level is at least 

 10,000ft. above the sea. Generally, the barometer is high 

 when they begin to appear. It then begins to fall, and a 

 northerly blow follows, sometimes within sis hours, more 

 generally after about twelve hours ; but occasionally it is 

 delayed for twenty-four hours, or even more. 



The appearance of these fish clouds may be that of small, 

 delicately-shaped, scattered fishes, in which case the follow- 

 ing north wind is generally not strong, and there is little or 

 no rain. If the fish-clouds be more massive, or if, as often 

 happens, they are joined together so as to form undulating, 

 eel-shaped clouds, with the characteristic smooth, hard, curved 

 outline above, then probably the northerly blow will be 

 strong, with rain. Sometimes the fish clouds are superim- 

 posed one on another, so as to form, as it were, a pile or piles 

 of fishes. This form is not so common, but I think it also 

 is followed by bad weather. 



So far I have merely dealt with observed facts, which I 

 hope others will also observe, if they have not done so al- 

 ready ; and it will be specially valuable to have instances 

 when northerly blows with rain have not been preceded by 

 fish clouds, or when fish clouds have not been followed by 

 the wind or rain. But, admitting that my observations are 

 correct, and that this form of cloud usually is seen before a 

 strong northerly wind, can we in any way account for it ? 

 We know that the great system of circulation in our atmo- 

 sphere, produced by the joint action of the sun's heat and the 

 daily rotation of the earth, gives rise to vast eddies in the air, 

 known as cyclones and anticyclones — the cyclones, or "lows," 

 if viewed from above, being like great saucers, rotating in this 

 hemisphere as the hands of a watch ; the anticyclones, or 

 " highs," like inverted saucers, rotating the other way. But it 

 is with the cyclones, or " lows," we are now concerned, as they 

 give us our strong winds and storms. The motion of the air 

 in a cyclone is very complicated : it is drawn inwards below, 

 it is poured outwards above, it ascends in a spiral course. 



