96 OUR HERITAGE THE SEA 



services to mankind, the cloud we have just men- 

 tioned, the nimbus. It is not the least of ocean 

 mysteries, the way in which its bitter waters are 

 suddenly, in a few minutes, converted into sweet, 

 drinkable fluid and elevated into the sky by thou- 

 sands of tons. There it is received and retained by 

 immense reservoirs of mobile shape, of entirely in- 

 tangible material, and conveyed by the agency of the 

 winds to those regions where it is needed. Pause a 

 moment and think of the utter marvellousness of 

 this miracle. The civil engineer planning the water 

 supply for a town must needs employ for the storage of 

 the water the strongest material and the utmost skill 

 in using that material, water being at once so weighty 

 and so insidious in its never-ceasing efforts to escape 

 from the confinement against which it rebels. More- 

 over, unless the engineer can find a source of supply 

 higher than the site of the town for which he has to 

 provide, he must of necessity instal, at tremendous 

 cost, vast pumping machinery, not only for the col- 

 lection of the water but for its distribution. And, 

 again, his sources of supply are liable to failure, to 

 contamination, to being tapped very likely quite 

 unconsciously by the engineers of rival or similar 

 schemes. Compare these costly hindrances, these 

 laborious preparations, with the simple ease of 

 Nature's inexhaustible supply. In the first place> 

 consider the celestial reservoir itself. There is no 

 matter for wonder in the fact of an enormous quantity 

 of water floating about in the sky in the form of 

 vapour as in the cumulus cloud, for really the mois- 

 ture in them is of the character of gas. But the 

 nimbus cloud, although of the same intangible, tenous 



