36 A NATURALIST ON THE " CHALLENGER." 



the water being thrown up a foot in height as it boils forth. A 

 constant column of steam rises from the basin. Near by is a 

 sort of fissure, from which issue at short irregular intervals jets 

 or splashes of boiling water mingled with steam and sulphuretted 

 hydrogen in abundance. This spring makes a gurgling, churning 

 sort of noise ; the large basin, a sort of roar. 



In the sides of the fissure grow, in the area splashed by 

 the hot water, some green lowly organized algae (Botryococus), 

 which form a thick crust upon the rock surface. Similar 

 growths of lowly organized plants in the water of hot springs 

 have been observed in various parts of the world.* At a couple 

 of feet distance from this hot spring rushes up a perfectly cold 

 iron spring with a considerable stream of water. 



All around are small openings, from which sulphuretted 

 hydrogen and other gases issue with a fizzing noise, and coat 

 the openings with bright yellow crystals of sulphur. The 

 ground around is hot, too hot in many places for the hand to 

 rest upon, and it is somewhat dangerous to approach the pools 

 of hot water at all closely, since the hard crust on the surface 

 may give way and one may be let fall into the boiling mud. 



Just above these hot springs is a beautiful mountain stream, 

 which forms little cascades as it tumbles down to the lake 

 valley from the fern-clad moor above. 



At the town of Furnas is an inn kept for families who come 

 in the season to drink the waters and bathe. There is a free 

 bath house built by the Government, with marble baths and hot 

 and cold mineral water laid on to each. The whereabouts of 

 the springs near the town are marked by clouds of steam. The 

 springs are scattered over a larger area than at the lake springs, 

 and the grey geyser formation is piled into irregular hillocks 

 around them, instead of presenting a nearly flat surface as at the 

 other springs. Here the principal spring is like that at the lake, 

 but the amount of hot steam rushing up is much greater, and 

 the noise is almost deafening. The water is thrown up about 



* For further account of the vegetable growths in the hot spring of 

 Furnas, see Linn. Journ. Bot., Vol. XIV, p. 321. Also papers on the 

 same by Mr. W. T. Thiselton Dyer and Mr. W. Archer, ibid., pp. 326- 



328. 



