PART ii. THE CYCLE OF A DAY. n 



by July in Madeira it had reached 9*4, in Lisbon it 

 attained to 19*3. And if, leaving means of the whole 

 months, we now cull from the experiences of single days, 

 we shall find that the highest point of temperature ever 

 touched in Madeira during sixty summer days was 79*3, 

 whereas in Lisbon it actually reached 98*3. 



Wherefore let those who desire to feel the real 

 warmth the summer sun is capable of imparting, by all 

 means rather visit Lisbon than its colonial dependency 

 Madeira, though it be actually several degrees of latitude 

 farther to the south ! 



Yet if Madeira be so much farther in that usually 

 sultry direction, why are solar excesses so little felt there ? 



The answer is, simply " Inquire of watery vapour.' ' 

 Not visible mist, or fog, or rain, which the beasts that 

 perish can perceive as well as man, but that invisible 

 quality in science known as " humidity," and which we 

 found to average monthly, even in the crystal -clear 

 atmosphere of Madeira, 73 and 74, but in Lisbon only 

 62 and 60. And, while the very smallest humidity ever 

 observed by us on a single day in Madeira was still 54, 

 we had twice proved it in Lisbon to be only 26. 



These meteorologically derived results were further 

 confirmed by spectroscopy, to whose searching glance 

 the optically invisible watery vapour stands forth marked 

 in darkness proportioned to its quantity. Thus the so- 

 called "rain band" of the pocket spectroscope averaged 

 an intensity of 3*8 in Madeira, but only 3*2 in Lisbon, 



