GEOLOGY OF THE FIRST DISTRICT. 
preceding, and from the second set of frames passes to a third in the same manner, until it is 
concentrated nearly to the point of crystallization. It is then boiled down, and crystallized 
in the usual way. These combinations of frames are several hundred yards in length, with a 
breadth of a few feet. Their length is placed in a direction perpendicular to that of the pre¬ 
vailing dry winds, in order that the greatest effect may be produced. The sulphate of lime, 
and other salts of moderate solubility, are deposited on the cords or brush, which, after a time, 
become coated with a solid stony crust of considerable thickness. This method is employed 
at the place mentioned, in evaporating water containing only one and six-tenths per cent, of 
salt, with considerable profit. The water is evaporated by this method to one-sixteenth,of its 
original volume, and then brought to the point of crystallization by boiling.* 
All these methods are capable of useful, and, it is believed, of profitable application on the 
southern coast of New-York. 
Muriate of lime occurs in almost all the spring waters of the Hudson valley, and parti¬ 
cularly in those that issue from the clay beds of the tertiary of that valley, and is the princi¬ 
pal cause of the “ hardness of the water,” or its quality of decomposing soap. In 1819, Prof. 
Eaton examined most of the waters from Albany to Blenheim in Schoharie county, and along 
the banks of the Hudson for more than one hundred miles, and also along the Boston road to 
Connecticut river; and in 1820 and 1821, Profs. Eaton, T. R. Beck and L. C. Beck, tested 
the hard waters of Albany and Rensselaer counties. In all these cases, the wells were in the 
marly clay, and contained muriate of lime.f The nitrogen springs contain muriate of lime.t 
5. Springs. 
- Springs are caused by the water percolating downwards from the surface of the earth, until 
it meets some stratum that is not sufficiently pervious to permit it to pass through. The 
water accumulates on this, until it rises to such a level as to find an outlet. 
Springs are the causes of many geological phenomena, with which it is important to become 
acquainted. The effects of springs in producing land-slides, and in depositing masses of cal¬ 
careous matter, have already been considered. Their effects in forming valleys, and in the 
transfer of various subterranean mineral substances to the surface, are yet to be discussed. 
Springs of water of ordinary purity, unless they be very large, produce but little effect on 
the surface along which they flow, except in a few instances, where, from local causes, or 
the exposure of particular strata, the excavating action is sufficiently obvious to be taken into 
account. When spring waters hold much mineral matter in solution, their effects are more 
marked, and have long attracted attention. 
The substances found in spring waters are numerous. The most common are lime, iron, 
magnesia, silex, alumina, soda ; carbonic, sulphuric, hydrochloric and hydrosulphuric acids ; 
• Silliman’s Journal, Vol. 20, p. 219; Mather’s Geological Report of New-York, 1837, p. 87; Vanuxem’s Geol. Report, N. Y. 
1841. 
t Eaton. Silliman’s Journal, Vol. 15, pp. 242, 243. J Eaton. Geol. Survey of Rensselaer county, p. 30. 
