302 ANNUAL OF SCIENTIFIC DISCOVERY. 



tube. This, from its vertical position, invites the water of the adjoining part 

 of the roof to descend along its outer surface, and now an exterior and more 

 rapid growth begins. Usually, the former process continues to operate for a 

 long time after the external growth has commenced : so that the stalactite, 

 in some cases, retains its open central canal until it has reached a length of a 

 foot or more, and a diameter at its base of two or three inches. As the water, 

 which flows along the outside of the tube, parts at each step with a portion of 

 its calcareous charge, and thus grows continually less capable of forming the 

 deposit, the rate of deposition must diminish somewhat regularly from the 

 upper to the lower end of the mass. Hence it is that stalactites, formed in 

 positions where their growth on all sides is freely permitted, have always a 

 sharply conical or tapering form. 



The drops which fall from these pendants to the floor, still retain a portion 

 of carbonate of lime in solution; but as the shock of the impact and the 

 spreading of the liquid greatly favor the escape of its carbonic acid, a further 

 deposit must be formed in this position, and thus the stalagmite grows 

 upwards to meet the stalactite growing downwards, until in many cases 

 they unite to form a column reaching from the floor to the ceiling of the 

 cave. 



As in general the infiltering water follows the joints and planes of stratifi- 

 cation of the limestone rock, the fashion or pattern of the stalactitic drapery 

 will be more or less determined by the position and arrangement of these divi- 

 sional surfaces. "Where, as in parts of "Weyer's Cave, in Virginia, these planes 

 of bedding are steeply inclined, and meet the roof in a series of parallel lines, 

 the concretionary action seems to have commenced by forming parallel rows 

 of stalactites along these lines. This process, in certain places, has gone on 

 until, by lateral union of the adjoining pendants of each row, they have been 

 transformed into parallel sheets of stone, which in some instances extend from 

 tl^e roof to the floor. From their great extent, and a degree of thinness 

 which, in part, renders them translucent, these sheets are capable of being 

 thrown into sonorous vibration by a blow from the heel near the ground, and 

 under these circumstances they emit a musical sound of great depth and 

 force. 



BOILING SPRINGS IN UTAH. 



The Placerville (Cal.) American gives the following description of ten 

 curious Springs situated about ten miles north of "Wash-ho Valley, Utah, 

 upon a tributary of the Truckee, and called " Steamboat Springs," appearing 

 to derive their name from the fact that they are like so many boilers generat- 

 ing steam. " For a distance of three-fourths of a mile do these remarkable 

 springs pour their waters, rushing, boiling, and foaming, through innumerable 

 fissures in the rocky formation in which they are found. The entire of one 

 bank of the stream on which they are situated, a distance of from thirty to 

 eighty rods in width and three-fourths of a mile in length, and rising back- 

 wards from the river in places from sixty to eighty feet, the whole seems one 

 vast deposit from the water that for ages has been ejected therefrom. It is 

 not that boiling hot water is ejected throughout this whole extent from well 



