VOYAGE TO ALGERIA. 163 



quickened pace. We turned to the left, so as to cut 

 across her bows. Five minutes' pull would have brought 

 us up to her. The officer waved his cap and I my hat. 

 ' If they could only see us, they might back to us in a 

 moment/ But they did not see us, or if they did, they 

 paid us no attention. I returned to the ' Urgent,' dis- 

 comfited, but grateful to the fine fellows who had 

 wrought so hard to carry out my wishes. 



Glad of the quiet, in the sober afternoon I took a 

 walk towards Europa Point. The sky darkened and 

 heavy squalls passed at intervals. Private theatricals 

 were at the Convent, and the kind and courteous Gov- 

 ernor had sent cards to the eclipse party. I failed in 

 my duty in not going. St. Michael's Cave is said to 

 rival, if it does not outrival, the Mammoth Cave of 

 Kentucky. On the 28th Mr. Crookes, Mr. Carpenter, 

 and myself, guided by a military policeman who under- 

 stood his work, explored the cavern. The mouth is 

 about 1,100 feet above the sea. We zigzagged up to it, 

 and first were led into an aperture in the rock, at some 

 height above the true entrance of the cave. In this up- 

 per cavern we saw some tall and beautiful stalactite 

 pillars. 



The water drips from the roof charged with bicar- 

 bonate of lime. Exposed to the air, the carbonic acid 

 partially escapes, and the simple carbonate of lime, 

 which is hardly at all soluble in water, deposits itself as 

 a solid, forming stalactites and stalagmites. Even the 

 exposure of chalk or limestone water to the open air 

 partially softens it. A specimen of the Redbourne 

 water exposed by Professors Graham, Miller, and Hof- 

 mann, in a shallow basin, fell from eighteen degrees to 

 nine degrees of hardness. The softening process of 

 Clark is virtually a hastening of the natural process. 

 Here, however, instead of being permitted to evaporate. 



