64 eepoet — 1879. 



at all, and there is then shown positive electricity of very moderate 

 intensity. 



The electricity, however, rises very rapidly, and comes to a maximum 

 at about half-past eleven o'clock, and seems to correspond very much 

 with the flow of the sea breeze — which the sun shining on the land causes 

 with great regularity — and also with the accumulation of masses of cloud 

 or watery vapour, which rise and coalesce to form a thin screen daring 

 the hottest part of the day over the basin of Funchal. 



It is curious that the index of the electrometer, which is extremely 

 unsteady and oscillating whilst the electricity is rising — probably from 

 the influence of masses of variously electrified vapour or air in motion — 

 becomes steady, and remains fairly steady for two hours or more — during 

 which time the maximum is maintained. The electricity then subsides, 

 as the cloud-screen breaks up early in the afternoon, at first suddenly, and 

 then very gradually until evening, when it faintly begins to rise again. 



The formation of the thin above cloud-layer over Funchal is very 

 regular, and occupies a vertical space of about 200 feet, at an altitude of 

 2,500 feet, varying slightly with temperature and atmospheric pressure, 

 and appearing, from a distance at sea, as a thin white sheet, beyond which 

 the black rocky peaks of the island shoot up for several thousand feet. 



The electricity below this cloud is always positive and moderately 

 intense ; in the cloud itself it is still positive, though feeble ; and above 

 the cloud, in a sheltered situation where these observations were taken, it 

 is still positive, though still more feeble, and very irregular. 



In warmer weather, as regards this cloud, the same conditions exist 

 exactly, although the moisture forming the cloud does not condense, but 

 appears from above as a dense blue transparent haze, liable, however, to 

 become opaque on any accidental puff of colder air. 



In my own garden I found that every observation was mitigated or 

 quite vitiated by the numbers of lofty trees closely planted together. 



The currents of air constituting the daily sea-breeze of Madeira are of 

 no great depth, perhaps 70 or 80 feet, and above the true wind blows in 

 the contrary direction. 



I have often succeeded in flying a kite through the sea-breeze into 

 the upper wind, and have made some attempts, abortive for want of proper 

 insulation, to bring down the electricity of the upper current. 



The electricity, however, of this upper current, which in fine settled 

 weather is the north-east trade wind, can easily be observed on exposed 

 mountain ridges, and always gives a steadily moderate indication of a 

 positive quality. Indeed, the only observations of the north-east trade 

 ever thought to have given a negative result were taken on a lesser peak 

 of Teneriffe with inferior instruments by Mr. Smyth, who, however, 

 attaches little value to them. 



For my own part I have not had a single observation of negative 

 electricity in the atmosphere at any time, if I may exclude faint oscilla- 

 tions of the needle, when there has been no ponderable quantity either way. 



In Madeira, at the termination of a long period of fine weather, on 

 the approach of rain clouds I have noticed a high electricity of a positive 

 character, very transient and irregular in character, and falling very low 

 when it actually rained. Rising electricity on the cessation of rain is 

 here, as in all other places, an important factor in forecasting weather. 



But Madeira is occasionally subject, especially in summer weather, to 

 another wind of very peculiar character. This is a kind of Sirocco, called 



