tJ08 Dr Webster’s Account of the Hot-Springs of Furnas. 
of the road, the beds of clay have been cut through to the 
depth of six or eight feet, and their structure is well displayed. 
The vicinity of the springs is indicated by the iiicreased 
temperature of the earth, a sulphureous odour, and the escape 
of vapour or steam from every crack and fissure in the ground. 
The temperature of the clay continues to increase as we ad- 
vance, and a greater quantity of vapour is at last seen slowly 
ascending from the springs themselves. 
The volumes of smoke and steam rolling upwards from the 
surface to a great height, till they are gradually diffused through 
the atmosphere, or mingle with the heavier clouds that crown 
the summit of the mountains, produce a striking effect. The 
confused rumbling and hissing noise that is heard for some time 
before we arrive in sight of the springs, increases at last to an 
incessant and terrific roar, and seems to issue from the very 
spot on which we stand. The earth retui’iis a hollow sound, 
and great caution is required to avoid stepping into the pools 
and streams of boiling-water, with which its surface is covered. 
The quantities of hot-water discharged through the innumer- 
able orifices in the ground, is prodigiously great, and the dif- 
ferent streams unite, forming a small river, that, still hot, joins 
the Ribeira Quente. The largest springs are termed Caldeiras, 
or boilers, and a shallow basin of earthy matter has been form- 
ed round each of them, by depositations from the water. 
Much of the water is constantly retained within these reservoirs, 
and its surface is more or less agitated by the escape of sulphu- 
retted hydrogen gas, and the ejection of the water from below. 
The temperature of some of these springs on the Sd day of 
December, between three and four o’clock P. M., the thermo- 
meter standing at 63° Fahrenheit, the barometer at 29.4, Was 
as follows : 
207 ° 
200 ° 
96 ° 
137 ° 
203 ° 
190 
134 
170 
73 
114 
184 
94 
122 
171 
147 ^^- 
The basin of the largest spring, particularly designated as 
The Caldeira,” is circular, and between twenty and thirty feet 
in diameter. The water in this boils with much greater violence 
• The above are put down' in the order in which they were examined. 
