These operations at Tarentum and Pittsburg led to an extraordinary attempt to fathom the petroleum-basin by _digging_ to the oil-bearing rock! Through Kier’s experiments the crude had become worth from fifty cents to one dollar a gallon. Among the owners of Tarentum’s salt-wells was Thomas Donnelly, who sold his well on the Humes farm to Peterson & Irwin. The senior partner, ex-Mayor Louis Peterson, of Allegheny, lived until recently to recount his interesting experiences with the coming light. He thought the Donnelly well, which produced salt-water only, if enlarged and pumped vigorously, would produce oil. Humes received twenty-thousand dollars for his farm. The hole was reamed out and yielded five barrels of petroleum a day. This was in 1856. A specimen sent to Baltimore was used successfully in oiling wool at the carding-mills and the total production was shipped to that city for eight years. Eastern capitalists bought the farm and well in 1864, organized “The Tarentum Salt-and-Oil-Company” and determined to dig a shaft down to the source of supply! The wells were four-hundred to five-hundred feet deep. The officers of the company argued that it was feasible to reach that far into the bowels of the earth with pick and shovel and discover a monstrous cave of brine and oil! They picked a spot twenty rods from the Donnelly well, sent to England for skilled miners and started a shaft about eight feet square. Over two years were employed and forty-thousand dollars spent in sinking this shaft. Heavy timbers walled the upper portion, the hard rock below needing none. The water was pumped through iron-pipes, nine men formed each shift and the work progressed merrily to the depth of four-hundred feet. Then the salt-water in the Donnelly well was affected by the fresh-water in the shaft, losing half its strength whenever the latter was let stand a few hours, showing their intimate connection by veins or crevices. Mr. Peterson said of it: “The digging of the shaft was finally abandoned in the darkest period of the war, from the necessities of the time. A New Yorker named Ferris, and Wm. McKeown, of Pittsburg, bought the property, shaft and all. The daring piece of engineering was neglected and finally commenced to fill up with cinders and dirt, until at last it was level again with the surface of the ground. You may walk over it to-day and I could point it out to you if I was up there. Dig it out and you will find those iron pipes and timbers still there, just as they were originally put in.”