422 CRITICAL NOTICES OF NEW PUBLICATIONS, 



This stratum is not permeable by water. Immediately under the coal, 

 there is a layer of soft clay, eight inches thick ; and, directly below this, 

 is another stratum of fire-clay, compact and several feet in thickness. 

 This last measure also is impermeable to water. Besides, the coal- seam 

 itself is so little pervious to water laterally, that a few yards of it are 

 sufficient to confine the water of old workings. Now, out of these facts, 

 which are absolute, the inquiry naturally arises : — how and whence is 

 this water derived. Did it pre-exist originally, as a saline fluid, in the 

 stratum ; or, is it a recent composition, resulting from a new chemical 

 combination of its elements ? If it was pent up in crevices when the 

 coal was first formed, or even subsequently, it would very soon be 

 drained off and exhausted. If the oxygen of the atmosphere furnishes 

 one of the ingredients of water, the other abounds in the coal ; but, 

 whence come the saline and other substances here so regularly and 

 uniformly combined with them ? Were they deprived of their oxygen 

 during the mysterious process by which the coal was formed ? Are they 

 now reproduced by the accession of oxygen from the common air ? Some 

 persons contend that this salt water comes into the line of the faults from 

 beneath, and diffuses itself in the coal. But, although the coal near the 

 faults, at particular spots, yields water, nevertheless, this comes not from 

 above, nor from beneath ; it neither drops downwards, nor boils up- 

 wards ; but, it issues in minute oozings at the sides. "When a fault has 

 been perforated, water is seldom or ever found therein, so long as the 

 confusion of strata, occasioned by the break, remains. On the other 

 hand, when the parallel strata set in, the coal yields the saline water at 

 almost every part. The fault might be a rent to an immense depth, but 

 the line of slip is filled up, and glazed by the pressure. Hence, in the 

 greater number of instances, where salt water is found and continues to 

 run, the source or formation of this fluid cannot be traced to the faults ; 

 for, although near some of these, the water is abundant ; yet, for the 

 most part, the borders of the faults, and the faults themselves, are 

 altogether without water and constitute actual barriers to it in every 

 direction. Salt water is found in one or more of the sandy rocks in the 

 superincumbent strata, but to no great extent ; and, it contains much 

 less muriate of soda than that which issues from the coal-measures.'* 

 These inquiries manifestly involve questions of extreme importance; 

 but, although difficult enough, their solution is a fair object of research ; 

 and, when ultimately attained, will conduce greatly, we are sure, in 

 accelerating the progress of natural philosophy. Mr. M., however, 

 deals with facts entirely ; and, in consequence, he abstains from ad- 

 vancing any theoretical explication of the phenomena here described. 



Chap. IV. — According to Mr. M. the polarity of strata is a subject 

 which hitherto has not been much understood ; and he regards the ex- 

 traordinary uniformity which prevails in the direction of the slines and 

 partings of the rocky strata, as having been determined by the operation 

 of some laws not yet understood. These partings or slines, he observes, 

 are smooth-sided, and run parallel to each other : sometimes they are 

 clear, sometimes have a little smutty or sooty substance in their inter- 

 stices : they are nearly vertical ; or, if the coal-seam inclines, they form 

 a square with its inclination ; and, where they are numerous, the coal is 

 got with more ease, and in forms more square than where there are 

 none of these natural divisions. Wherever slines appear, their direction is 

 32<» west by north, whatever way the stratum may incline, and the coal 

 between them has an arrangement of lines parallel to the slines, by 

 , which it may be divided. At right angles with these, another set of 

 lines prevails ; and these last, with the lines of clearage, give a centric^ 



