CHAPTER II.

Submarine Blasting,—Erie Harbor,—Dimon’s Reef, N. Y.,—Coenties Reef, N. Y.,—Oil Wells, Penn.

In the winter 1869, 1870, I received a communication from the engineer in charge, Major G. Clinton Gardiner, formerly of the United States Boundary Line Survey, concerning the harbor improvements in Erie, Penn., under W. A. Baldwin, General Superintendent of the Philadelphia and Erie Railroad, with a view to blasting in the harbor of Erie, so as to furnish from 15 to 17 feet of water for vessels laying alongside of their wharves, instead of carrying them (the wharves) into deep water; these operations were entirely successful, and I subjoin the report of Major Gardiner to General Parke, U. S. Engineer Corps, written previous to dredging. The certificates of Mr. Baldwin, Superintendent; F. J. Wilson, Ass’t Engineer; Chas. F. Dunbar, contractor for the dredging, follow Major Gardiner’s report. These certificates it will be observed, were given after a considerable portion of the rock had been removed by the dredging machine.

Letter from Major G. Clinton Gardiner to General John G. Parke, Corps of Engineers, Washington City, D. C.

Office of Philadelphia & Erie Railroad.
Erie Harbor—August 2nd, 1869.

To General John G. Parke, Corps of Engineers, U. S. A.

My dear General: Some days ago I received a letter from Mr. Geo. M. Mowbray, who is the patentee of a most valuable improvement in the manufacture of Nitro-Glycerin. He being interested in having his material used in the improvements at Hell Gate, requested me to report upon the experiment in blasting at this place. Being unknown to General Newton, and having no time for a report, I take the liberty of writing to you on the subject.

Since leaving the United States Boundary Survey, I have been employed on the Philadelphia and Erie Railroad, under the direction of the Ass’t Gen. Superintendent, Mr. W. A. Baldwin, in the improvement of their dock at this terminus of the road. The water at the end of the main pier and for a short distance inshore, on either side of the pier, is over 14 feet deep, shoaling back to about 6 feet, which we had to deepen to 14 feet. The bottom is a smooth hard surface of shale rock, a portion of which when exposed to the air disintegrates, while other parts are sufficiently hard, and are used for, building purposes. It lies in strata of about eight inches to twelve inches thickness, which we drilled through and blasted during the winter, and are now dredging the rock. The process of drilling was in the primitive style, with hand drills, mostly done through the ice, and the blasting, with powder in cartridges with small tubes reaching to the surface of the water, through which the match was conducted to the powder. Firing however, was afterwards done by dropping a red hot nail down the tube, which was quite an improvement on the match, and gave us almost simultaneous explosions. The holes drilled were 5 feet apart, in rows of 5 feet from each other, and the largest charge of powder used was a canister 2 inches in diameter and 40 inches long. This process having been used to some extent the season before, it was commenced again this last winter, but the work being extended, we thought it advisable to make some improvements in the modus operandi. After a correspondence with different manufacturers of machine drills, we found no one of them ready for business at once, and before we were able to make terms, our primitive style of drilling advanced almost to completion. We sent to Mr. Mowbray who was then in Titusville, Pennsylvania, to try his Nitro-Glycerin, and made an experiment in a square of a little over ten yards, where the rock to be removed was over seven feet deep. The holes were drilled a greater distance apart, but to the same depth as used for powder (15 feet from surface of water). In this square we blasted about 230 square yards of rock, using 50 pounds of Nitro-Glycerin in cartridges fired in rows by electricity, but without a face of rock to work from, such as we had with the powder blast. This would have taken 125 lbs. powder. Upon reaching the place with the dredge, we found the rock completely crumbled, rendering dredging as easy as that of gravel, and to the depth of seventeen feet, while with the powder blasting we have had trouble, and in two cases had to blast again to obtain fourteen feet of water, and even then have to lift rock measuring ten and twelve cubic feet. Nitro-Glycerin is certainly far superior in its effect, and would have been much cheaper to use in this case. Gunpowder does not blast to the depth of the holes drilled, whilst Nitro-Glycerin tears the rock from the bottom, and here seems to have penetrated three feet beyond. The reason it was not used before, was the difficulty in procuring it. The nearest factory was that of Mr. Mowbray at Titusville, and the local as well as state laws were such that it could not be transported, except by private conveyance, which added to its cost. That used was carried to Corry in Mr. Mowbray’s carriage, over a very rough road, and thence by special train to this place. If pure, the danger in the use of Nitro-Glycerin is no greater than that of powder, and the premature explosions that have proved so fatal in many instances, have without doubt been caused by decomposition, which was the result of imperfect manufacture. If regularly manufactured, accidents will be the result only of inexperience or the neglect of instructions from those having experience. In the manufacture, the nitrous vapours that are disengaged at the time of mixing, if not entirely expelled, will make it liable to explosion from any concussion, and from Mr. Mowbray’s experience in a number of instances with that manufactured by himself, I should judge his Nitro-Glycerin to be as safe as powder in the hands of experienced persons. It is of a light yellowish color, with pungent aromatic taste, rather sweet than otherwise, and is so poisonous, that in handling, should one allow it to remain on his hands, it would produce intense head ache. It does not explode from the application of flame to its surface, yet will burn, but explodes only from severe concussion, as by the explosion of detonating mixtures and fulminates.

I write to you hoping you will communicate any information my letter may contain to General Newton, as it may serve Mr. Mowbray, who I think has made a great improvement in the manufacture of Nitro-Glycerin, and as he gives it his personal attention, I have no doubt it is superior to any now used.

I was much pleased to receive the report of the blasting in California, and should interesting professional papers be published by the Bureau, let me beg you will remember

Your sincere friend,

G. Clinton Gardiner.

The experiments above narrated and conducted under the supervision of Major Gardiner, were continued, (on the removal of the Major to the Pennsylvania Central’s works at Altoona,) by F. J. Wilson, under General Superintendent Wm. A. Baldwin, and the results expected were entirely fulfilled, as will be seen by the subjoined communications:

Submarine Blasting with Nitro-glycerin; Results as Compared with Blasting Powder, in Erie Harbor, May, 1870.

Philadelphia and Erie R. R.; Pennsylvania R. R. Co., Lessee.

Office of the General Superintendent,
Erie, Penn., May 19th, ’70.

To Geo. M. Mowbray,
North Adams, Mass.,

Dear Sir: The comparative values of the two materials, Gun-Powder and Nitro-Glycerin, as to results and actual cost for blasting in the harbor at Erie, cannot be positively obtained until the dredging is finished; when this year’s operations with Nitro-Glycerin, can be compared with that of last year done with powder. The prospects thus far are so favorable, however, I regret that the use of Nitro-Glycerin was not adopted last year.

On the completion of the work I shall be pleased to furnish you with statements of comparative results, feeling confident they will prove a more full satisfactory and valuable endorsement of your Nitro-Glycerin for submarine use, than any theoretically based opinion can be.

I enclose you copy of reports of Mr. F. J. Wilson, Engineer in charge of Erie Harbor Works, and of Mr. Dunbar, contractor for dredging, which will give you an idea of the economical results to us from the use of your Nitro-Glycerin.

Yours truly,

Wm. A. Baldwin, Gen’l. Supt.

Erie, Penn., May 16th, 1870.

Wm. A. Baldwin, Esq.,
Gen’l. Supt. P. and E. Railroad.

Dear Sir: Below please find a statement of comparative cost of drilling and blasting where Nitro-Glycerin is used. The 1240 lbs. of Nitro-Glycerin were used over an area of 26,700 sq. feet, with an average depth of rock of about seven and seven-tenths feet, making 11,500 cub. yards of rock measured in the bed.

The difference in favor of Nitro-Glycerin in dredging and in time saved is not taken into consideration in the above (see Capt. Dunbar’s letter).

Very respectfully,

F. J. Wilson, Ass’t Engineer.

Erie, May 18th, 1870.

To W. A. Baldwin, Esq.,
Gen’l. Supt. P. and E. Railroad,

Dear Sir: In reply to your inquiry as to the relative difference in dredging rock blasted by Nitro-Glycerin and that blasted by Powder, I have no hesitation in saying that I am certain we can dredge twice the number of cubic yards where it is blasted with the Nitro-Glycerin. I think I could speak safely and say three yards to one where the rock is hard. In fact, there are places where we could do nothing with the Powder blasting, when we have no trouble with the Nitro-Glycerin.

Truly yours,
Chas. F. Dunbar,

Firm of Lee & Dunbar.

Result.—Submarine drilling and blasting with Nitro-Glycerin costs 44½ cents per cubic yard. Gunpowder costs 66¾ cents per cubic yard. Nitro-Glycerin used, one ounce and six-tenths of an ounce per cubic yard of rock removed.