1883.] on Weather Knowledge in 1883. 333 



than it is in Scotland, a motion of cirrus from north-west indicates 

 the existence of a depression situated to the west of us, and as that 

 depression advances on us the first wind we shall feel will be south 

 or south-east, certainly not north-west. 



Similar rules have been laid down for cirrus motion in other 

 azimuths, and from its rate conclusions may be drawn as to the motion 

 of the depression whence it takes it rise. 



This seems exceedingly promising, but now comes the other side 

 of the picture. Mr. Ley himself admits that the faculty of cloud 

 observing is incommunicable by simple teaching. The motions of 

 these clouds are so gradual, and are apparently so liable to be con- 

 founded with the motions of other and lower strata, that a great 

 exercise of judgment is requisite before an opinion is pronounced. 



Supposing, even, we have only one stratum to deal with, the head 

 must be kept immovable during the period of observation, and the 

 motion of the cloud across or past a fixed object, like a chimney, 

 watched. Lastly, the observations cannot be always taken at fixed 

 bours, at the fixed observing epochs, but must be made whenever 

 Dpportunity offers. The observers, therefore, must have abundance of 

 leisure, and that is a commodity hard to meet with in these busy 

 iimes. 



What is, then, the general conclusion we can draw as to weather 

 knowledge and its prospects in 1883 ? I have endeavoured to show 

 y'ou that iveatlier knowledge is practically iveatlier -prediction, and that, 

 ^or the seasons, in Europe at least, no trustworthy basis for predic- 

 :ion has as yet been established. 



For the daily forecasting of weather much has been effected, but 

 nuch more remains to be done, and the most important advance we 

 ;an make is in the direction of training observers in the difficult art 

 )f upper cloud observation, the most promising field of study at 

 )resent. 



The enquiry into Atlantic weather which is now being carried on 

 n our Office, and which enables us to prepare daily weather maps of 

 he ocean with nearly 400 observations on each, will, it is hoped, 

 brow light on how and where some of the storms which visit us "take 

 heir rise, but it will certainly show what actual condition over the 

 •cean accompanied each manifestation and movement of cirriform 

 louds at our stations, and will thus afford data for laying down rules 

 o determine the position and track of a storm-centre before it reaches 

 ur coasts. 



Cirrus observations are in fact the only practical means we have 

 f, so to speak, annulling our insular and isolated position, and of 

 xtending our outposts over the Atlantic. 



[K. H. S.] 



