C6 REPORT — 1855. 



the surface of the earth in the form of rain, and that of its final issue in the 

 form of springs. The quality of spring-water, and indeed of that which 

 flows only over the surface, varies constantly according to the geological 

 character of the district on which it falls, or through which it passes. 

 Thus most of the primitive rocks and many of the secondary ones, being 

 composed of comparatively insoluble ingredients, impart little or no change 

 to the water ; while others, such as the old and new red sandstones, limestone, 

 chalk, the rocks of the lias and oolitic formations and clays generally, are 

 more or less acted upon by the water, imparting to it in various degrees a 

 portion of their mineral or chemical constituents. Hence spring-water varies 

 considerably in its character ; and though, when not impregnated by mineral 

 substances, it is generally agreeable and wholesome as a beverage, it is fre- 

 quently unfitted for culinary and domestic uses, as well as for delicate pur- 

 poses of trade, by reason of its chemical ingredients and its excessive hardness. 

 Dr. Clark of Aberdeen has invented a convenient mode of determining the 

 relative hardness of water by the application of a soap-test. By his rule, 

 " each degree of hardness indicates as much hardness as would be produced 

 by one grain of chalk per gallon, held in solution in the form of bicar- 

 bonate of lime free from any excess of carbonic acid A quantity 



of a soluble magnesian salt, equivalent to one grain of chalk, destroys a like 

 quantity of soap-test, and consequently indicates one degree of hardness. 

 The same is the case with the salts of iron and salts of alumina ; salts of 

 alkalies do not produce hardness." By this test it requires about 4° of 

 hardness, according to Dr. Clark's scale, to break or curdle soap. By the 

 use of this test it is shown that distilled water being zero, or possessing no 

 hardness at all, rain-water, as freshly caught in towns, is generally from 1° 

 to 2° of hardness. The springs which issue from such primitive rocks as 

 granite or gneiss, from the mica-slate and clay-slate formations, from the 

 millstone grit and from the greensands, as they are developed in Surrey, vary, 

 with some exceptions, from about 1° to 3° of hardness; all these formations 

 yielding water of the greatest natural purity. The springs of the new red 

 sandstone vary generally from 5° to 20°, and the limestone- and chalk- waters 

 from 10° to 20° of hardness, while those which issue from the lias and oolite 

 run up to 30° and upwards. 



I need not mention mineral springs and spa-water. 



The chemical character of water has only recently been attended to, but 

 in the selection of a water for the supply of a town, there is nothing more 

 Important than careful chemical investigation. 



The instances of supplies of water being derived from springs, although 

 the mode commonly adopted when towns were small and the demand for 

 water limited, are now becoming rare ; but it may be interesting to mention a 

 few cases, and to give the particulars of some of the more important springs 

 which have been appropriated or proposed to be applied for that purpose. 

 The city of Edinburgh was, till a recent period, supplied by springs 

 collected in the Pentland Hills, and scrupulously guarded from ail admixture 

 with other water by the very able engineer of the Water Company, Mr.Jardine. 

 The supply, however, proving insufficient, recourse has been had to the sur- 

 face-water collected in large reservoirs, for which object very extensive works 

 have just been completed by Mr. Leslie, the present engineer to the Company. 

 The whole district of the Staffordshire Potteries, comprising a very large 

 population, is now supplied by a magnificent spring of very excellent water 

 issuing from the new red sandstone in the valley of the River Churnet near 

 Leek, which, after being raised by engine-power to the summit of a neighbour- 

 ing height, is conducted several miles by iron pipes, supplying the district by 



