were chosen for comparison with lithia because the last-named base seems in most of its relations to hold an intermediate place between the former two, with which it is closely allied. Chlorid of barium was also prepared with all the precautions needed to ensure its purity, precipitated twice from its aqueous solution by alcohol, and recrystallized three or four times. It was at last obtained as a fine crystalline powder by stirring the hot saturated solution as it cooled, and this powder was allowed to dry spontaneously in the air at a temperature of about 80° F. Thus prepared, the salt-as Marignac has shown-is not altered in weight by further exposure to air, its theoretical composition is BaCl+2HO, the precise amount of water actually present was probably a little greater, owing to the mode of drying, but was unimportant under the conditions of experiment adopted. = For each of the six weighed portions of sulphates mentioned above, the quantity of chlorid of barium needed for exact precipitation was calculated, assuming the equivalent of sodium =23, that of magnesium =12, that of lithium =7, and that of barium 68.6, and considering the chlorid of barium as containing strictly two atoms of water. Six portions of the lastnamed salt were weighed out (at the same time), each less than the amount calculated by one or two centigrams. Each was dissolved in 200 cubic centimetres of hot water, and added to its corresponding portion of sulphate, likewise dissolved in 200 cub. centim. of hot water. The fluid and precipitate in the six beakers were well stirred, and left to settle. A solution was now prepared of 1 gram of the crystallized chlorid of barium (weighed out at the same time with the larger portions) in 1 litre of water, each cubic centimeter corresponding therefore to 1 miligram of BaCl+2HO. With this standard solution, dropped from a pipette whose degrees = 4th of a cubic centim., the precipitation of the fluid in each of the six beakers was completed the amount of chlorid of barium thus employed was noted, and added to the weight of the main portion originally taken. At first it was easy to observe the formation of a precipitate on each successive addition of the chlorid of barium solution, and subsidence took place quickly; but, as the point of exact neutralization was more and more nearly approached, each observation became more difficult, and hours and even days were required in order to observe the production of a cloud by each drop added, or to get the fluid clear again for another trial. When the last addition of chlorid of barium altogether failed to produce a precipitate, a single drop of a solution of sulphate of soda was added, and the formation of a cloud noticed. In this way the following results were obtained : A, 1.-3.8924 grm. of LiO, SO, required for complete precipitation 8.6323 grm. of BaCl+2HO as used. A, 2.-4.6440 grm. of LiO, SO, required 10-2940 grm. of Baci+2HO. B, 1.-5.0675 grm. of NaO, SO, required 8.6920 grm. of BaCl+2HO. B, 2.-5.1107 grm. of NaO, SO, required 8.7688 grm. of BaCl+2HO. C, 1.-4-3380 grm. of MgO, SO, required 8-8318 grm. of BaCl+2HIO. C, 2.-4.6625 grm. of MgO, SO, required 9-4872 grm. of BaCl+2HO. Calculating now from B, and C, the amount of crystalline chlorid of barium necessary to precipitate an equivalent of NaO, SO, or MgO, SO,, we get the following numbers, which represent what may be called the practical equivalent of the chlorid of barium as actually used. the theoretical equivalent of BaCl+2HO being 122.1-the presence of any water over the normal two atoms tends to raise the practical equivalent-the presence of any BaCl in the precipitated BaO, SO, has the same effect, the presence of either of the soluble sulphates in the same precipitate leads to an opposite result. From this practical equivalent of chlorid of barium and the results given above under A, 1, and A, 2, we may calculate the equivalent of lithium. If we adopt for chlorid of barium the number 121.80-that obtained by the precipitation of NaO, SO, -we have for A, 1, 54.95-48-6·95=Li. The mean of the two results is 6.935. If we take for chlorid of barium the number 122.12-derived from the experiments with MgO, SO,-we get by a similar calculation, Lastly, if we take the mean of the two numbers for chlorid of barium, namely, 121.96, we get for A, 1, 2, or, in the mean, 7-005. Li=6.99 Li=7·02 Hence, we find, that the equivalent of lithium, as deduced from the mean results of the above experiments, comes out 6.935 (=86-69 on the oxygen scale) 7.080 (=88-49 " “ or as we take the practical equivalent, or actual precipitating power, of chlorid of barium from the experiments with NaO, SO,, those with MgO, SO,, or the mean of the two, these numbers exhibiting close agreement, and obviously indicate 7 as the true equivalent of the metal. It will be observed that the above method is independent of a knowledge of the exact equivalent of barium, and uses chlorid of barium merely as a means of bringing sulphate of lithia into comparison with the sulphates of soda and magnesia-the equivalents of the two last named bases may be considered as ranking among those best established -and the small difference between the practical equivalents for chlorid of barium deduced from these two shows the probable extent of error involved in the assumption of the same constant in the precipitate of the sulphate of lithia. While these results confirm those formerly obtained by the analysis of chlorid of lithium, I do not consider them of superior or perhaps even of equal value. The estimation of chlorine by the method of Pelouze is apparently one of the most simple and exact processes for the determination of an atomic weight which have ever been proposed, and it is, as I believe, fully applicable to the case of chlorid of lithium. As the result of both sets of experiments we may fairly take the number 7 (=87.50) as representing the true equivalent of the metal. ART. XXXVIII.-Notes on certain Ancient and Present Changes along the Coast of South Carolina; by OSCAR M. LIEBER, State Geologist, S. C. It is very evident that remarkable changes have taken place on the coast of South Carolina during the present geological epoch; changes, which have effected or are yet, effecting very conspicuous alterations in the contour of the coast as well as in the hydrography of the immediate interior, and the elevation and character of the land. Five or six prominent effects of change I think may thus be distinguished: I. An ancient depression along our coast. II. A total change in the course of the portions of the rivers near the coast. III. A more recent superficial elevation of the coast and→→ VI. A southward translocation of our littoral islands. Of the ancient depression of the coast we find an indubitable proof in the piles of oyster shells accompanied by charred wood and Indian pottery, found in ditching the rice fields sometimes at a depth of five or six feet, and near the level of low tide at a distance of thirty miles frequently from the mouth of the river, (as at Mr. Langdon Cheves' plantation opposite Savannah). This fact also seems to indicate that the coast must, at the time that these oyster piles were formed, have been far nearer, for the distance from the sea would be too great to render transportation likely. It also shows the gradual rise of the land by surface accumulation, of which, of course, there are many other indications in the fertile alluvium of the rice-lands. The formation of some of these rice-lands is itself connected with a remarkable change in the general character of the seaboard. Let us take Cooper river for instance, as that affords one of the most remarkable cases in the State. Any map of moderate accuracy will show that the length of this river bears no proportion to its width. At the same time it is accompanied on either side by wide bodies of alluvial accumulations, which could not possibly have had their origin in material derived from the adjacent country, which, with the solitary exception of an occasional bluff of eocene marl, (as at Mepkin), is a region of pure and coarse sand, whose effects, wherever it is washed into the rice-lands, is materially injurious. The rice-lands themselves are composed of a rich tough loamy soil having at times a thickness of sixty feet (d in Fig. 2, B in fig. 1), containing no visible organic remains-not even infusoriæ, as Dr. E. Ravenel informs me-but perfectly homogeneous in its composition. Upon this substance rests a stratum composed either of the remains of marsh grass or of drift-wood and bay-roots, &c., according as the surface is more or less exposed to the tidal inundations of salt water. This stratum is observed at CC in fig. 1. In those places where it is regularly covered by salt water, the accumulations of the whitened shells of dead mollusca are often visible even at a distance. CC is evidently a far newer formation than B and altogether distinct in its origin. There are cases, for instance close to Dr. E. Rav enel's residence, where the stratum, CC, may be observed to extend into the adjacent sand bank, while at another point on 1. C the same plantation the drift wood contained in this bed, was struck at a considerable distance from the edge of the bank. D, therefore, assumes the appearance of a drift-sand. A, may either represent earlier sand strata (probably post-pliocene, but containing no fossils), clearly marked, highly fossiliferous post-pliocene clays and marls, or the more durable eocene marl beds. In some places the bed, CC, presents an extremely light, semipeaty mass of greatly increased thickness (as on Savannah river: Mr. Cheve's plantation, &c.), when dry it ignites with the greatest ease, leaving scarcely any ash. Of this feature advantage has been taken to reduce it to the level of the rice-fields now in cultivation, where its natural elevation and more inland position raises it above the tidal irrigation, it is then annually burnt off. For one year it will then yield a good corn crop, by repeating the operation its level is gradually reduced, and the land which it covers rendered available to rice-culture. (L. C's plantation.) We have seen that the stratum, CC, often underlays the adjoining sand hills, while the far more massive bed, B, terminates abruptly on striking either the marl-bluffs or the solid sandbanks. CC, is therefore not the more recently accumulated part of B; but entirely independent. With rivers like the Savannah, the Santee and the Pedee we find the source of the mass B at once explained by the presence of those water-courses. But with rivers like the Combahee, Ashepoo, and especially the Ashley, Cooper and Wandoh, no such existing source is visible. The present streams do not extend sufficiently far into the interior, nor do they drain sufficiently fertile regions to have been able to accumulate so very rich a deposit; yet they are the very ones, where this stratum is observable in its greatest development. If we notice the great ramifications of the swamps of this region, the solution, how |