Hard shells and slate 15 to 1665

Hard shells 5 '* 1670

Sand and pebbles 8 "' 1678

Slate and shells 82 " 1760

Drilled dry. Cased 450'

Conductor 15'

Salt water in slate 445 to 540'

"" red rock 1528 to 1535'

Smell of oil reported in sand 1670 to 1678'

The Olean Conglomerate is probably represented in the record by the sand from 30 to 85 feet below the top of the well.

The records of the Bear Creek and Silver Creek Wells are invaluable as having a direct bearing upon the probable existence of petroleum to the south and south-east of Wilcox.

It will be noticed that the mass of the red rocks are some :>00 feet lower in the the Bpar and Silver Creek Wells than in the Wilcox Wells, estimating from the bottom of the Olean Conglomerate.

The question as to whether the mass of red bands in the two localities are the same and whether the strata included between them and the Olean have thickened to the south and south-east, is extremely suggestive.

Xote.—The records are published just as they have been reported to me. I have not even altered the phraseology, which is quite different in a number of places where the same idea was evidently intended to be conveyed.

I will merely add, for those who are unacquainted with the terms employed by the drillers, that "shell " means any hard stratum encountered in the well, and not, as might he supposed, a fossil.

Nature's Reforesting. By Eli K. Price.

(Rend before the American Philosophical Society, September 20, 1878.)

The paper on Sylviculture read in November and December, 1877, has produced the following confirmatory letters of views therein expressed. They are from the present Chief Justice of Pennsylvania, who lives in Beaver, and the Professor of Botany in the University of Pennsylvania, formerly a resident of Mifflin County, Pennsylvania.

Continental Hotel, February 11, 1878.

My Dear Sir :—I have read the address you sent me on Sylviculture

with great interest, especially as some of its facts have come under my own

observation. The western part of Pennsylvania was once among the best

wooded portions of it, yet the destruction of timber has plainly affected 1STS.] ^ • [Price.

springs and streams. Many of the springs have become wet weather water courses, while the floods in the streams rise suddenly and high, and subside as quickly ; the rainfall running rapidly over the denuded surface, and failing to penetrate it, as when shaded by the forest, and covered with leaves and weeds.

There is a curious fact I have never read of, yet which displays the effort of nature in the spread of vegetation. In July, 1837, I returned home from the Constitutional Convention, which sat in Harrisburg. When passing along the canal in the valley of the Juniata, I noticed long reaches of stone covered mounlain sides, bare of all vegetation from base to summit, and of most curious structure, the stones being, apparently, comminuted rocks, so small and flat as to have come to a regular inclination at angles, varying probably from twenty-five to forty degrees. After I began to come to that city to the sessions of our Court, passing upon the Pennsylvania Railroad, I occasionally looked for some of these naked stone mountain sides without seeing them. At first I supposed this to be accidental, my attention happening not to be drawn to them at the proper time. In the course of time I began to think I was mistaken, and that these bald spots had disappeared. I was led to look more closely and continuously, and saw a few left, but greatly diminished in extent, and some mere clots between growing trees. At last I discovered mountain sides covered with a very small growth of trees, mere shrubs in size. The last time my attention was given, I saw one large space of mountain side covered with the small flat stones before described, and in it here and there a single sapling or shrub or two standing alone, proving that from leaves or other vegetable matter deposited by the winds, soil had begun to be formed, and vegetation to grow. From what I have noticed of other stony mountain sides covered with large timber, along the same valley, I conclude that there was a time when all these mountains were similar rocky, and stony surfaces, bare of all vegetation, and left by the convulsions of nature just as she cast them up.

I am very truly yours,

DANIEL AGNEW.

Hon. Eli K. Price.

Beaver, August 26, 1S7S.

My Dear Sir :—On my return by the Pennsylvania Railroad last week I discovered at several places the evidence of the fact I stated to you last winter in regard to the growth of timber on the bald stony surface of the Allegheny Mountains. I am now perfectly satisfied of the truth of my suggestions. I saw distinctly the remaining uncovered surface as of comminuted stone in patches small and great, the young growths of shrubs and sapling interspersed, with here and there one shrub in a bare patch, indicating the beginning of covering and the different stages of progress.

The first point I noticed was about seven or eight miles west of Mifflin —the second at lfilst mile to Pittsburgh—the third at 152d mile to Pittsburgh—the fourth 140th mile to Pittsburgh, and the fifth just east of the Spruce Creek Tunnel.

An examination of these places I have no doubt will show them to be constantly arising.

Yours Truly, &c,

DANIEL AGNEW. Hon. Eli K. Prick, Philadelphia, Pa.

West Chester Co., Penna., August 29, 1878.

My Dear Mr. Price :—Your letter was received yesterday. Owing to the work constantly pressing me I have been unable to get away more than four days this summer. During that time I passed (in train) along the line of the Pennsylvania Central Railroad and in the narrows of the Juniata between Mifflin and Lewistown, and my attention was called to the fact that on a number of rocky places all the timber was small and of recent growth. This is at or near the places mentioned by Chief Justice Agnew, and in so far may be regarded as confirming his views, when taken in connection with the fact that extensive and destructive conflagrations appear to be less frequent there than formerly. Being raised in that region, I can remember when for miles the mountain sides each year were a line of fire. Though I have not been there of late years much of my time, I still feel justified in the statement that such events are now of rare occurrence. Fires doubtless do originate each year along the line of the Railroad, but they do not appear to spread far and wide as before.

Touching the motion of the rocks as preventing growth; I can only give as an instance the old mountain road between McVeytown and Kishacoquillas Valley. This ran through some of the most rocky places in the region, and where the slope was very steep, and indeed almost undermined them on the upper side. For years this road was practically abandoned, at least no work was done upon it. I do not remember the place where the rocks had slidden enough to close the road. Indeed these very places were favorite places of growth for the Purple Flowering Raspberry (Rubua odoratus) and the Hydrangea arboreieens. Motion here must have been very slight.

It is a source of great regret to me that I have not been able to take the time to go into a full investigation of this matter. As it is one of interest, and closely associated with my line of work. I believe that the large rocks allowing the snow and rain to find its way readily to a considerable depth have also favored carrying the soil in the same direction (and then away). Professor Hayden alluding to similar places in our western domain, offers this as an explanation of the scarcity of large trees there.

Very sincerely Yours,

J. T. ROTHROCK.

I believe Major Powell in his report, published or about to b'e published by Government, goes into the question of destruction of forests by fire very fully, and presents the case in a very strong light.

West Chester, Chester Co., Penna., September 3, 1878. Dear Mr. Price:—Since writing to you I find the following statement in a lecture by Prof. Gray of Cambridge, on "Forest Geography and Archaeology" quoting from Professor Shaler of Kentucky—"Professor Shaler from his observations in the border land of Kentucky thinks that there are indications there of comparatively recent conversion of oak openings into prairie, and now since the burnings are over, of the reconversion of prairie into woodland." The passage in the first part of the quotation refers to Shaler's opinion that fires have destroyed the forests there. This you know is in entire accordance with what is said on pages 276 and 277 of Michaux Travels, published in 1805 (Lambert's translation), of exactly the same region.

Sincerely yours,

J. T. ROTHROCK.

Professor Leo Lesquereaux has formed the opinion that the prairies have failed to produce trees because of a soil inimical to their growth. This theory appears to be successfully combatted by O. P. Hay in the American Naturalist for May 1878, p. 299. It is also contrary to many facts stated in "Sylviculture." The last page of that paper contains the conclusion of O. W. Wight, in his Geology of Wisconsin, who said, "Fire has killed the timber over wide areas, on which grass was growing, exhibiting before our eyes nature's simple method of reconverting woodland into prairie. The reverse process is just as simple. When prairies are no longer swept over by fire, timber springs up, reconverting prairie into woodland. Grass, with fire as an ally, can beat timber. Timber can bent grass, when it has no fire to fight." We may also add that without fire to fight it can conquer stones and root itself beneath the rocks, and be anchored all the stronger. It is ever man that is the great destroyer, and he is competent to repair his own devastation.

Contributions from the University of Pa., No. XV. Preliminary notice on Ghromomelry, a new branch of quantitative analysis with the blowpipe. ■

By Professor George Aug. Konig, Ph. D. With A Plate.

{Bead before the American Philosophical Society, Oct. 4, 1878.)

In a former paper presented to the Society (Proceedings Vol. XVI., January, 1877), I described a coloriraetric estimation of titanium. Mention is made in that paper of the interference with accurate results by the presence of metals producing green glases in the reducing flame, such as vanadium or chromium, the green being complementary with the red of titanium and thus destroying the latter. That method is purely colorimetric, as the determination depends on a comparison of color intensity with glass beads containing known quantities of titanium. But the mutual extinction of complementary colors led me, already at that date, to seek & way for the utilization of this principle, as expressed in the same paper: "I am now experimenting upon the feasibility of extinguishing the color of titanium by a graduated scale of green, etc' Finding, however, some serious practical obstacles, I allowed the subject to rest until the present summer, when perfect leisure favored a more successful pursuit.— I now place before the Society the result in a preliminary form, reserving for a future paper the details and the special determinations, as well as tables, for a number of tne most important minerals and ores.—The new method of analysis I propose to name "chroinometry," for I measure the quality as well as the quautity of certain colors, both isolated and when combined with other colors not their complementaries, these latter being the determinants. Thus, iron imparts to borax in the exydizing flame a dark red-brown color while the bead is hot, which passes into pure yellow at the ordinary temperature of the air. Under the same conditions mimsinese produces a purplish-red glass, both together a brown glass in all shades from pure yellow to pure red, according to the relative quantities of the two metals. If this glass be looked at through a certain thickness of a tiansparent green medium, such as green glass—the red will have disappeared and a pure yellow will be seen; increasing the thickness of green medium ever so little, will cause a greenish yellow color to appear, whilst an equal reduction in the medium will cause a brownish yellow tint. The human eye is much quicker to appreciate a change of shade, than a small change of intensity of color, as those well know, who are accustomed to the polarization of sugar.—In this instance I designate the pure yellow as the point of extinction, while colorlessness or any other simple color may represent extinction in other cases.—Thus it will be understood that the new method analyses the colore, what colorimetrj* of liquids as heretofore applied does not, it involves another principle and should therefor be called by another name.—Chromometry seems to express the essential" of the method very well "a measuring of color" besides being a purely Greek compound noun, not Latin-Greek, as Colorimetry. The new principle of analysis by complementary colors is applicable to both liquid and solid transparent colored bodies, but I shall confine myself for the present to the solids exclusively.

In regard to their behavior towards borax and microcosmic salt—the metals are chromatic (imparting characteristic colors to these fluxes) or achromatic (imparling no color, or no characteristic color).—The chromatic series comprises: copper, nickel, cobalt, iron, uranium, chromium, vanadium, tungsten, titanium, manganese, molybdenum, niobium, ilmenium, neptuuium. All of these metalls fall within the capacity of chromometric