I detect in the mineral in a few instances, by the aid of the microscope, minute plumbago-like scales or lenticular crystals, which do not appear to be plumbago, or even specular iron.

As the phosphate is represented as existing in quantity, it suggests a valuable source of phosphoric acid or even of phosphorus itself. How it can be utilized in agriculture does not appear so

obvious.

Charleston, South Carolina, Feb. 13th, 1869.

2. Final Report on the Geology of New Jersey; by GEO. H. COOK, State Geologist. Published by the Board of Managers, Newark, 1868.-This volume forms a handsome octavo of 900 pages, with 108 photographic engravings and wood-cuts, and six mine maps. It is accompanied by a portfolio containing four large colored maps in seven sheets, illustrative of the extent of the Azoic, Paleozoic, Triassic, Cretaceous and Tertiary and recent formations in the State, forming a complete geological map drawn to a scale of half an inch to the mile. Also four other maps in five sheets showing, (1) the group of iron mines in Morris County, printed in two sheets colored and drawn to a scale of three inches to the mile, (2) the Kingwood Iron Mine, (3) the Oxford Furnace Iron ore veins, and (4) the Sussex County Zinc Mines, the last three drawn to a scale of 8 inches to the mile. This volume is the final report of Prof. Cook of the survey authorized by the State in 1864. It also embodies in it much of the material contained in the annual reports of the survey of Dr. Kitchell made in 1854-6, but interrupted in 1857, by failure of appropriation from the State. A brief sketch of the general geography of the State forms the introduction, followed by some 300 pages devoted to the detailed and historic geology, while more than one half the book is devoted to economic geology.

Confining our observations exclusively in this notice to the "economic" part of the work, we are pleased to see a recognition of the well established fact that soil analyses are of but little benefit to farmers, although a few analyses are very properly given to show the general nature of the soils of the State. A chapter on limestones and lime gives many valuable facts and analyses, and this is followed by a discussion of the chemical characters and remarkable fertilizing properties of the greensand marl, which of late years has assumed great commercial importance as a fertilizer, no less than 134,000 tons of this material having been transported on the New Jersey railroads during the past year.

Not only "green" sand but "white" sand is very extensively

66

pitted" in New Jersey, nearly 20,000 tons of the latter being annually produced for glass making, and consumed by some forty glass houses in the southern part of the state.

The clays of New Jersey are also of great economic importance; the fire clay of Perth Amboy, South Amboy, Woodstock, and other places in Middlesex County, is shipped to all parts of the Eastern and Middle States, and thousands of tons of it are annually made into fire-brick.

We are glad to see so large a space devoted to the consideration of the Iron ores and the description of the iron mines; this chapter together with the admirable detailed map of the Morris County, Kingwood and Oxford Iron Mines, forms an exceedingly interesting feature of the book. Prof. Cook gives the product of the iron mines of the state as 300,000 tons in 1867, while in the furnaces 36,919 tons of anthracite pig-iron, 9,000 tons of charcoal pig-iron, and 5,980 tons of bar iron from bloomeries and forges were produced the same year. Of zinc-ore, Sussex County produces 25,000 tons per annum, which is manufactured into white oxyd and spelter, yielding 7,000 tons of oxyd, and 500 tons of metallic zinc. Prof. Cook estimates the total amount of zinc-oxyd produced yearly in the United States to be 10,000 tons and spelter 2,300 tons. Our space permits us to touch on but a few important points. The book is made accessible to almost every one, as it is furnished to those who desire to purchase it at the mere cost of paper and printing, all the expense of preparation and illustration being defrayed by the state.

We add here only that the scientific value of the volume is much increased by an Appendix, containing Catalogues of the Invertebrata of the Cretaceous and Eocene formations of New Jersey, by T. A. Conrad; of the Extinct Mammals and Reptiles, by Prof. E. D. Cope; of the Minerals, by Rev. E. Seymour; and of the living Vertebrata of the State, by Dr. C. C. Abbott.

III. ZOOLOGY.

1. Are Unios sensitive to light? by ISAAC LEA. (In a letter to the Editors of this Journal.)-In the March No. of this Journal, page 286, Mr. C. A. White heads an article with " Are Unios sensitive to light?" He then gives some experiments which he instituted on the subject, and he seems to be under the impression that his observations were entirely new.

If your readers will turn to the Proceedings of the Acad. Natural Sciences of Philad., for 1857, they will find a communication from me where the subject of touch, hearing and sight in the Unionida was pretty fully stated. It will be found in my paper that I experimented on various species of the family and pointed out some which gave no indication as to sensitiveness to light, while others were particularly sensitive, especially the Unio radiatus Lam. I there stated that the visual organs were placed on the fringes of the siphonal opening. That "with a good lens the terminal point of the tentacula may be observed to be rounded and furnished with at least the appearance of an eye and that it

would prove to be a true eye, however imperfect, there can be little doubt." I also stated that I left the subject to Dr. Leidy, believing that "he would be able to make out the complete anatomy of the eye of the Unio."

It was mentioned also in this paper that the females were more sensitive to light than the males.

Subsequently in the introduction to my vol. 6 "Observations on the Genus Unio," &c., I mentioned the subject again, and stated. that I had found that the Unio rubiginosus Lea, U. Cylindricus Say, and An. imbecillis Say, were all sensitive to light.

On referring to my notes made since the above mentioned publication, I find that during the years 1858, 59, '60, I found the following species "very sensitive to light," viz., Unio subrotundus Lea, U. pyramidatus Lea, U. obscurus Lea, U. pustulosus Lea, U. Esopus Green. The further investigation of the subject is well worthy the attention of malacologists who are so situated as have all the conveniences of exploration, investigation and time.

IV. MISCELLANEOUS SCIENTIFIC INTELLIGENCE.

1. On the use of sodium in explosive powders.-Dr. H. FLECK of Dresden has made an extended series of experiments on the use of sodium as an ingredient of various explosive and inflammable mixtures, mainly with the purpose of replacing phosphorus in the match manufacture. In his earlier attempts he simply added sodium to ordinary gunpowder; but it united with the sulphur and thus destroyed its efficacy. The sulphur was then omitted from the compound, which was formed of 8 grams saltpeter, 2 grams sodium, and 1 gram charcoal (mixture A); it was a gray mass which flashed like gunpowder on being touched with a moistened glass rod. On filling a tube with gunpowder, placing a little of this powder on the top, and throwing the whole into water, an instantaneous explosion took place. This mixture, however, burned too rapidly to ignite sulphured wood; the charcoal was therefore replaced by antimonous sulphid and a mixture made of 66 grams saltpeter, 365 antimonous sulphid, and 5 grams sodium (mixture B). This is preferable to the former one because it contains less sodium, the reaction being:

3KONO,+Na+SbS, NaOSbO ̧+зKOSO ̧+зN.

The next point was the preservation of the sodium. This Fleck has succeeded in doing by means of paraffine, under which the sodium is melted, and then very finely divided by violently shaking the flask for five or ten minutes. A granular powder of a silvery luster is thus obtained, which when removed from the still liquid paraffine, does not tarnish, being perfectly protected by a thin coating of this hydrocarbon which it retains, and which increases its weight from 30 to 35 per cent. 66 grams of this sodium are substituted for the 5 grams of ordinary sodium in the above mixture B. To remove all traces of moisture from the other ingredients, they are well dried and then moistened with petroleum; the sodium is now added and the whole is well mixed together in a metallic

mortar, until it becomes a uniform powder; it is then preserved in well closed vessels. As thus made, A is in the highest degree inflammable, communicating the combustion readily to the mixture B on a piece of sulphured wood. For the purposes of the match manufacture, these mixtures are made into a paste with caoutchouc dissolved in naphtha to a gelatinous mass, which then may be readily incorporated with the powder, without injuring the inflammability of the latter.

Experiments were then made on the preparation of a suitable match box, one which should act when opened. A brass box, whose cover was made to fly open with a spring, was filled in its lower part with moistened asbestus; in the upper portion, two compartments were arranged, separated by a spring slide. The upper one contained the spontaneously inflammable pellets. On opening the box the slide is automatically opened and one of these pellets falls through the opening into the second compartment, and thence through a second opening on to the moist asbestus, where it is at once inflamed. The pellets are composed first, of a doughy mass of chalk and the caoutchouc paste; this is then dipped in a mixture of 3 parts potassic chlorate and one part golden sulphid of antimony, also made pasty with the caoutchouc solution; while still moist they are shaken with the pulverized mixture B, and placed in the upper part of the match-box, which holds about 100, each being about 2 mm. in diameter. All who have seen this match-box in use have been surprised at the ease and certainty of its action; and were it possible to make the slide air-tight, it must come into general use.

Another purpose for which this mixture has been used is the preparation of primers, which are ignited when pierced by a moist needle, whose point carries an eye in which the water is lodged. It has also been employed with success in the manufacture of pulling torpedoes. And the inventor suggests its applicability for firing the charges in blasting, either under or above water. For this purpose the powder is contained in a glass tube whose mouth is closed with melted sodic hyposulphite. On immersing the tube in the vessel containing the gunpowder, and placing the whole in water, the explosion follows so soon as the hyposulphite is dissolved. Ten milligrams of the powder is sufficient to ensure the ignition of the heaviest charges.-Dingler's Polyt. Journal, exc, 306, Nov. 1868.

G. F. B.

2. Decrease in the Production of Gold.-BLAKE in his late "Report on the Precious Metals," has the following remarks on the probable future decline in the production of gold, which are worthy of notice (p. 233); as also those on placer and vein mining and the probable rise in value of gold, to be quoted hereafter.

"The statistics of the production of gold in California, Australia and other countries show very clearly the familiar fact that in all newly discovered gold regions a maximum production is soon attained and is succeeded by a gradual but certain decrease owing o the exhaustion of the placer deposits. Thus, in California the maximum product was attained in the year 1853, when the

shipments were about $55,000,000, and the production was doubtless from $60,000,000 to $65,000,000 in value. It is now much less than half of that amount. In Australia, in the same year, (1853,) the reported shipments from Victoria amounted to 3,150,020 troy ounces, and the production was nearly $60,000,000 in value.* In 1867, the shipments were only 1,433,687 ounces, much less than half as much as in 1853. The apparently nearly uniform production of California for the past ten years, judging from the shipments of treasure from the port of San Francisco, is the result of the opening of other gold and silver producing regions in Nevada, Idaho, Oregon, and Arizona, which, so far as their production depends upon placers, are in their turn liable to rapid exhaustion. In British America and in Idaho and Montana the production of gold is now rapidly diminishing.

"Russia is the only country in which a nearly uniform production has been maintained through a series of years. This may perhaps be explained by the fact that the mines have not been free to all, and consequently comparatively few persons have been engaged in developing them. The climate, also, is unfavorable to rapid and continuous working, and the method of washing placer gravel by machinery in use there is necessarily slow and gives limited results, which cannot compare with those obtained by the gigantic system of sluicing practiced in California, and Australia. There has also been in Russia a constant extension eastward of the gold region by new discoveries, extending even to the Pacific coast, and there is doubtless an immense area of virgin ground from which the gold supply of Russia may be for a long time maintained at the present figures, or, possibly, greatly increased, especially if all restrictions upon mining are removed, and the country is thrown open to the skilled miners of other regions. This Siberian gold field, with the great mountain region south of it, extending into China and India, is the only extended region now known in regard to which there is any uncertainty in respect to its probable future yield of gold.

"The existence of very ancient workings in the Altai is significant, and leads us to question whether this great interior region has not already yielded up its most accessible treasures."

3. Dana's System of Mineralogy.-The first thousand of Dana's Mineralogy having been disposed of by the publishers, a new issue has recently been made, with some corrections, of which the following are the most important:

Page xxii, 25th line from foot, 3 for 3; p. 60, 21 1. from foot, 7.671 for 6-671; p. 77, 6 1. from foot, 743 for 47.3; p. 150, in fig. 148, 5 for 53; p. 252, in line of 297, MEIONITE, in 2nd formula, for ; p. 259, 8th 1. from foot, 3·97, 3.87 for 2.97. 2.87; p. 262, 14 1. from top, Levy, Jahrb. Min. 1830, 71; 16 1. from foot, iv, 513 for iv, 147; p. 290, in fig. 272, 1r for 11; p. 309, in fig. 285, for 2. 2 for below, and for I; p. 320, under fig. 291, ii for I; p. 327, in fig. 292, below 0, 2 and 3 removed to right of and 1; p. 366, in fig. 333, i-2 transferred to next plane to the right; p. 383, in fig. 362, i3 for the lower i2; p. 409, 14 1. from top, Ueberroth for Ueberroble; p. 448, 31. from foot, H2 for H2; p. 480, 31. from foot, 1840 for 1837; p. 495, 19 1. from top, 1841 for the first 1843; p. 530, in fig. 441, 2, 1, 2 substituted

*Calculated at $19 per ounce.