down 150 feet. I made the excavation at a time when the water was in the ground, and kept it down by pumps from the outside. I laid a series of tile from bottom of the tank to the center.

Over that I laid oak plank, 12x3. I broke the joints, and put a crosswise covering of planking of similar thickness, leaving only an open space, where my pump was placed, in the center. On top of the planking I laid two courses of brick with Louisville cement. I then placed a 14-inch pipe in the central opening and kept on pumping the water up. I built an arch around the pipe and filled in with cement, keeping the pump running, and had everything complete and ready so as to let the water in when we stopped pumping. I filled the tank to the height of a foot, disconnected the pump, and put the cap on. I never had any difficulty at all with that tank. I like the Rosendale cement because it sets so quickly.

MR. MCMILLIN-It will not set half as quickly as the Portland article.

MR. LANSDEN-I have used Portland cement but very little.

MR. CLARK—Recently I read about the experience of a former Superintendent of the New Orleans (La.) Gas Light Company, gained while building a holder. The soil there is alluvial with quicksand below. He had almost reached the bottom when the quicksand began to pour in. He drove sheet piling downdo not remember to what depth. He got it finished one night, but the next morning he had three feet of sand there. He tried it again. Then the sheet piling that had been driven down began to rise. Bricks were hauled in and placed on top of the piling until there was a ton of weight to each foot. This kept the piling down, but still the sand was coming up, and the ground was lowering outside. The earth seemed to be seeking its own level. The tank structure was finally accomplished by taking out 20 feet at a time all round, and starting a man in with concrete the moment a particular section was ready. When a section was secured the sand did not give any trouble. No wall was built un

til the whole thing was bottomed. Putting in the concrete saved it. In the meantime, the diameter of the tank had been diminished by 14 inches. That tank never leaked. The water in that

locality stands in the soil at a point within three feet of the surface; but after the tank was finished not a drop leaked in.

MR. THOMAS—I do not think, as a general thing, that the great difficulty in building tanks lies so much in the walls as it does in the bottoms, although I fully agree with everything that Mr. Spice has said in relation to their construction. A short time since I was called on to examine a tank which had been built in a wet, mucky place, and the tank bottom had been covered with only seven inches of concrete. Under the concrete a 10-inch pipe had been run in from the well on the outside of the tank, extending under the wall three or four feet into the tank. The well was on the side of a hill; and I suppose the point where the well discharged over the surface was, probably, ten feet below the tank coping. After the tank was built they pumped the water from the well into it. The pipe leading from the tank into the well was about six feet above the well's bottom. When they commenced pumping the water over into the tank it was drawn from the bottom of the well; and as they progressed with the pumping sand made its appearance. In fact, they were simply pumping out the bottom from under the concrete. They had a sort of "perpetual motion" going on. After they had pumped the water up above the orifice of the well, of course, the fluid ran out. On taking up the tank bottom, the mason work, concrete, etc., was found to be completely honeycombed. The water was running everywhere under it. After the bottom was made good, the pipe was plugged tight on the inside, and then water was pumped into the tank-care being taken to raise the pipe in the well so as not to pump from under the tank. After filling the tank with water this time it proved all right, and I think it is to-day as tight a tank as may be found in this country.

MR. A. C. WOOD-I have had some little experience in building gasholder tanks, having built several at our Syracuse (N. Y.) works, and have also done similar work for other gas companies I have in all cases succeeded in making a good job. One of the most important points is, as Mr. Spice remarked, to use good material. I once built a tank for a 100 foot gasholder, where the inside tank was 1031⁄2 feet, with about the dimensions Mr. McMillin spoke of in his specification. The ground was lower

The

by 15 feet on one side of the lot than it was on the other. excavation was in the bed of an old water course. I had a good foundation until I began to approach the bottom of the excavation, which was, of course, in gravel and boulders. As we uncovered, the water came up in large quantities all through the bottom. It was not, according to the nature of the situation, expedient to there excavate an annular space; but I intended to leave a cone in the center about 15 feet high. We got it down to 6 feet, when along came a very rainy season, and the water almost flooded us at times. We were then obliged to suspend excavating and commence on the brickwork. I had about six feet head of water coming up from this gravel to counteract; and it would flow up to the six feet level in half an hour. Having plenty of boulders and cobble stones at hand, I built a wall to the outside of the work. That kept us free from the water. We put in the bottom concrete in four courses, each course being three inches thick. We built brick walls. About every seventh course we had a solid brick wall, with inside and outside courses of brick laid in mortar with tight joints. The bricks were pounded close together and grouting placed between. Nothing but square bricks were laid. Every course of brick was inspected-not only on the contract jobs, but also on our own. In that way we got a water-tight tank. I have succeeded in building tanks in that way without any trouble. I remember building a small tank on the side of a hill having a clay bottom -the blue clay being about two feet thick on top of the quicksand. The water-course was at the foot of the bluff. We experienced some little difficulty there. If you can only confine quicksand you can build upon it as well as upon any other foundation. Another important point to be considered is the proportion of the material used. Mr. McMillin and several other gentlemen speak of using one-half hydraulic cement. I think that we are very apt to make our mortar too rich, and to depend too greatly upon the virtues of the hydraulic cement. We have a very good cement with us, and I have always used it in building our tanks. We employ what bricklayers usually term a "third," but it is really a "quarter"—one part of hydraulic cement and three parts of sand. With that we have always succeeded in getting a tight job.

MR. BOARDMAN-I have a great deal of faith in concrete holding water. I built a reservoir holding two and one-half million gallons of water, and lined it entirely with concrete. There is not a single break in it; it is as tight as can be. A roadway has been cut through the land within less than fifty feet of that tank, the roadbed of which is about three feet above the bottom of the reservoir; and in that roadway seldom is there seen any water leaking through. There is nothing but concrete in it; and the concrete was composed of one part of the cement to four parts of gravel and sand.

Mr. STEDMAN-Lest some of our new members might be discouraged by hearing of the hardships the older members have been through in excavating and building tanks, I want to say that we put one up at Newport, R. I., thirteen feet below tide water, the base of brick-work being twenty inches thick, whilst the least thickness of same reached sixteen inches. The tank was 102 feet six inches in diameter on the inside, and the bottom was covered with eight inches of concrete. That was all the work that was done on it. It was perfectly tight from the first. In that excavation the annular system would hardly do, because we had to blast through about sixteen feet of solid rock. I suppose that even Mr. Spice will admit that the annular system of excavation would not have done there. I want to say with regard to the statement made just now about the absorption of water by brick, that we put cement on the surface of the bricks to prevent them from absorbing the water. The mason who built the tank for me had had quite an experience in building such work, but he insisted on putting two courses of bricks on the bottom, else he would not guarantee the tightness of the tank. I said if he would omit the bricks I would guarantee its tightness. I knew the quality of the cement was good, and there was no doubt it would be tight. Some one has spoken about water in a tank lowering two feet by reason of absorption of the fluid by the bricks. I would be suspicious of bricks of that sort.

On motion of Mr. Thomas, the thanks of the Association were tendered to Mr. McMillin.

Mr. W. H. Denniston, Supt. of the East End Gas Light Company of Pittsburgh, Pa., read the following paper on —

NATURAL GAS:

There is no apology necessary, and so none is offered, for the writing of this paper. The reason for its preparation, shortly and simply stated, is that I was asked by our Secretary to prepare an article on the subject of "Natural Gas," and I returned him an affirmative answer. If the choice of subjects had been left with me this one would not have been selected; but I have undertaken it in the hope that a short article, of modest pretension, as to experience with, or knowledge of, the subject, would open up a discussion on the question, so that others who are more able, and have had greater experience in the premises, might debate the various phases regarding its utility (also the probable results), and the likelihood of its becoming a competitor with coal gas as an illuminating or fuel agent.

I remember at our last meeting one of our members thought the subject hardly worth discussing, because of the limited extent of territory where natural gas was to be found, and because, the prospect of its approaching to anything like an important competitor of coal gas was too remote.

Since that meeting there has been a regular boom in natural gas. Within the past few months large sums of money have been expended in developing gas territory, and even in “wild catting" and prospecting. Of course, it is known that natural gas has been found in a great many places—indeed nearly all over the world; also that in many of the States and Territories, and in Canada it has been discovered in paying volumes, and utilized in salt manufacturing operations, and as fuel for steam boilers, etc. Ten years ago, or when I was interested in producing oil, I remember how pleased we were to obtain from one of the wells a strong flow of gas. It was used under several boilers at first; then as the pressure weakened a fuel supply for only one boiler could be obtained; and finally we had again to return to the use of coal. In very many places, therefore, it was known and used to a limited extent, but this present general utilization of natural gas is of quite recent growth. In my own immediate neighborhood (Pittsburgh, Pa.) where a short time ago the capital invested was counted by thousands, and where it had been in use to some extent for years, there are now millions of dollars in