332 Mr. B. H. Scott [May 4, 



of Olland's Telemeteorograph on the tower of Utrecht Cathedral, but 

 the obtaining of records from such an elevation as can be secured on 

 the loftiest buildings, is not obtaining them from the upper currents 

 of the air, and we have yet to prove the practicability of raising an 

 electric thermometer to a height of, say, 2000 feet, and maintaining it 

 there in all ordinary weathers, before we can say that much is to be 

 expected from mechanical uj)per current observation. 



Lastly, we come to optical modes of observing the condition of the 

 air above us. These are the only ones which as yet give us much 

 encouragement, and of them I shall only mention two. Spectroscopy 

 and Cirrus Cloud Observations. 



The former has an enthusiastic advocate in Professor Piazzi 

 Smyth, whose repeated letters to the newspapers have at least 

 attracted the notice of many who have not seen his copiously 

 illustrated work on the subject, " Madeira Spectroscopic." Professor 

 Smyth maintains that by observations of his rain-band in the spec- 

 trum, he can form an accurate estimate of the amount of moisture 

 susjiended in the air. This belief of his is not as yet, however, 

 accepted as an article of faith by meteorologists at large, and, even if 

 it were, it still remains to be proved how much warning of coming rain 

 such phenomena will aiford. If they only give it for a few hours, 

 the advantage they present to us is not very material. 



Under any circumstances there are great obstacles to the general 

 introduction of spectroscoj)ic observations at telegraphic reporting 

 stations. The instruments arc comparatively costly, and their use 

 requires more skill and delicacy of handling than we can expect from 

 men of the rank of our ordinary telegraphic reporters. 



Lastly, we come to the observation of the clouds, especially of the 

 upper clouds, which has been of late almost reduced to a science, 

 mainly by the labours of the Eev. W. Clement Ley in this country, 

 and of Professor H. Hildebrandsson of Upsala in Sweden, around 

 whom a knot of observers are gathering. Mr. Ley is the most 

 enthusiastic, and also by far the most experienced of the authorities 

 upon the subject, and he said of himself in a lecture delivered a few 

 years ago, that he had spent yV part of his waking existence in 

 watching cloud motion. What he advances therefore must be received 

 with due respect. 



For his own district, the Midlands, he claims to be almost 

 infallible as regards weather, when he can secure an observation, and 

 from our experience of his telegrams to us his announcements for the 

 country in general are frequently astonishingly correct. In few words, 

 the principle which he applies is the motion of the highest stratum of 

 clouds, the " cirrus " of Howard and its relatives. He has shown that 

 the various motions of these clouds can be explained by the view 

 that the air slowly whirls out of a cyclonic area in the upper strata, 

 in directions opposite to those of the wind motion at the earths 

 surface. 



Thus for instance, when pressure is higher over France or Germany 



