12 MADEIRA METEOROLOGIC. PART n. 



while my large solar spectroscope was still more pro- 

 nounced ; for though, in Lisbon, the water vapour lines 

 forming the group known as "little a" were generally 

 few and as thin as fine spider lines, in Madeira they were 

 mostly thick, black, and crowded together. 



Now this remarkable agreement of these most diverse 

 indications for invisible moisture does so demonstrate the 

 importance of attending in the present day to something 

 more than the barometer and thermometer of former 

 times, that we cannot stop here ; but, from the cycle of a 

 day, must go on to ascertain what takes place in the far 

 longer cycle of a year, and over a wider geographical 

 extent than the little step between Lisbon and Madeira. 

 I have not, indeed, sufficient original observations of my 

 own to elucidate this part of the case; but have been 

 collecting and condensing from many good observers, 

 and with such results as the following. 



