•fSOi), 310] LIMESTONE OF RANKIN, L85 



309. From Byram, the limestone may be traced in occasional 

 outcrops to the neighborhood of Brandon, where it, appears at 

 numerous localities, generally capping the hills (as on A. P. Miller's. 

 Jos. Jayne's and Rev. I). A. Campbell's land,) forming a belt run- 

 ning N. E. and S. W. 



There are here also, however, several ledges of hard limestone, separated 

 from each other by strata of white marl (ii 218). The heaviest stratum, which 

 appears at the same level in several localities in the neighborhood, occurs at 

 Yost's lime-kiln. This stratum is composed of two ledges, separated only by 

 a thin sheet of soft material ; the upper ledge, about two feet in thickness, 

 consists of disjointed blocks, very jagged and rough, and its cavities tilled with 

 red clay from the surface. The lower ledge is solid, and 2% to 3 feet thick ; 

 it is blue internally, but yellowish on the outside, there being, however, no 

 essential difference between the portions so colored. An anatysis of a specimen 

 of this rock, taken from the lower ledge, gave the following result : 



LIMESTONE FROM YOST'S LIME-KILN, RANKIN COUNTY. 



Insoluble Matter (chiefly fine Sand 2.029 



Lime 52.474 



Magnesia 0.667 



Peroxide of Iron, and Alumina 2.125 



Phosphoric Acid 0.075 



Carbonic Acid 41.529 



Water 1.100 



99.924 

 One cwt. of this limestone will therefore yield about 57 pounds of lime, of 

 which about 4V 2 ' lbs. are impurities. 



310. The lime made from this rock, when properly burnt, slakes well, and is 

 suitable for all purposes. It has, nevertheless, been thought to be greatly inferior 

 to the imported — to make the mortar less firm, and not to admit of as large an 

 admixture of sand. There is not. in the nature of the material, any reason 

 why this should be so ; but I have perceived abundant cause for these effects, 

 ua the manner in which the burnt product is often managed. It has been 

 allowed, after burning, to lie on the ground in piles, in open sheds, and has thus 

 keen sold in small quantities, after having lain for weeks and even months. 

 Under such circumstances, the purest and strongest lime will rapidly become 

 useless, for it is thus afforded an opportunity of returning to the same condition 

 from which it was originally changed by burning, and in consequence, it loses 

 its property of hardening when used as mortar. When burnt lime is thus 

 allowed to become airslaked, it increases considerably both in weight (more than 

 one third) and volume ; so that the purchaser not only buys a worthless article, 

 but also pays for it higher by giving the same price which he would have paid 

 for the freshly burnt product. 



Burnt lime, in order to preserve its fitness for use in mortar, must be kept 

 from contact with the air as much as possible. It ought therefore to be barrelled 

 or boxed immediately, if destined for sale or transportation ; and not as apples 

 ©r oranges are, simply in order to keep them together, but tightly, like flour, etc. 

 When, however, a kiln of lime has been burnt for use on the spot, and it be 

 inconvenient to use it at once, it may be kept with perfect security and without 

 danger of deterioration, by slaking it in the same manner as though it were to 

 be converted into mortar at once, but afterwards letting it off from the slaking- 

 pan into a pit in the ground. After a time the lime settles, leaving the super- 

 fluous water on top, which as far as practicable may be drawn off ; after which, 

 fche pasty lime is covered over with sand to the depth of several inches. — Pure 



