mass is removed and spread out, and exposed to the atmosphere for reoxidation. The mass was found to purify more gas on each succeeding trial, until the iron was thoroughly oxidized.

The iron, sawdust, etc., in quantity sufficient to charge all of the purifiers, and a surplus for changing, costs about the same as the lime used for purifying during a period of four months, and after is used without cost except for labor, which including remass from the purifiers, ventilating, and replacing, is not far from the cost of slaking lime, charging and emptying the boxes, with the same.

The statements of expenses are probably not new to most of you, gentlemen; but having been requested to present them, I do so with pleasure, as I desire to add my mite to the interchange of opinion on the great subject of gas making.

It was moved and seconded, that the paper of Mr. Hyde be received and placed on file, with the thanks of the Association.

Carried.

Mr. Clegg-If in order, I would like to request a statement from Mr. J. E. Condict, of New York City, on the subject of the manufacture of coal gas. We are full of petroleum, but I should like to hear something about the new system of making gas from coal alone, as now carried on at Yonkers.

Mr. Condict-Mr. President, and gentlemen of the Association: I regret that the engineer of the works referred to the Yonkers Gas-Light Company—is not present here to-day, that he might read a paper which he prepared, on the process now used at those works. If I had expected to bring this subject before the Association, I would gladly have prepared a paper showing the manner in which the process is carried on. By referring to the diagram herewith presented, you can readily see how the new benches are constructed at Yonkers, and in what respect they differ from the old setting.

I will not take up your time, gentlemen, to go into any chemical analysis of this process, but simply state a few commercial facts, which may serve as a basis for your opinion as to the value of this system.

A bench of six retorts was constructed, exactly as you see on the diagram, in September, 1873, and about the first of the following month it was fired up, and for nine consecutive months, without the intermission of a single hour, was kept in operation. The net results of using Westmoreland coal (with the exception of two tons of Murphy Run coal) in continuous running for nine consecutive months, averaged 12,000 feet of gas, of over 17 candle power, per ton of coal.

After it had been working thus two or three months, the engineer of the Yonkers company, Mr. Slade, came to our works in New York and made a test. A week later he made a second, and on the following week a third. These tests not only embraced all the matters pertaining to details of manufacture, the quality and permanent character of the gas, but also extended to every mechanism employed, within or without the works, from the scales for weighing the coal, to the consumers' meters for measuring the quantity of gas sold.

On his recommendation a bench was constructed at Yonkers. That bench, after running three or four months, and proving satisfactory, was followed by the changing of the entire works to this process. It is of interest to all of the stockholders in every gas company, and to every gas engineer, to know the simple fact that we can get 12,000 feet of 16 to 17 candle gas out of Westmoreland coal, as against 9,500 feet by the old process. You will notice, by referring to the diagram, that it has a bench of six retorts. The three connected retorts on the right, and three on the left, form two entirely independent series, the lower and middle retorts of each side being connected by a stand pipe, as shown in the drawing, and the middle and upper retorts in the rear, by an

We charge all three of the connected retorts on one side of the bench simultaneously, and at the end of two hours, the three on the other side, and the gas is worked off in the same length of time as in the ordinary process.

Retort A communicates with B by vertical pipe between mouthpieces A and B; and B with C by tile opening T. All of the retorts are charged with coal; the upper retort, "C," being charged the heaviest. No super-heated steam, oil, naphtha, or enriching coals are used.

opening at the back end, through two saddle-ties placed side by side.

The candle power was tested by three separate photometers, and found to average over 17 candles. We had another practical test. The gas was used in several large buildings, and one or two manufacturing establishments that used gas from other gas companies, and it was a common thing for us to go in these places, at the request of friends, and turn off our gas, and turn on the gas of other companies. Thus we had an option of comparing the illuminating power of our gas with that made by the old process, and the comparison fully justifies the assertion that gas made by this process was up to, if not exceeding, the standard of that made by either of the other companies. There is no loss in coke; we tested it again and again, and the average we found to be from thirty-three to thirty-five bushels of coke to the ton, and of fully the same commercial value as coke from the ordinary way. There is no extra labor involved on the part of the workmen. By the old process, you make tar at the expense of the gaseous product. We make only about three to four gallons of tar to the ton, as compared with the old process of twelve to fifteen gallons. During the nine months that the bench was in operation, and making during that time more than six million feet of gas, the retorts were not cleaned once, and they are as free from carbon (with the exception of a very small collection in the rear end of the upper retorts) as the day they were placed in the benches.

The first bench constructed at Yonkers has been running six months, without the intermission of one hour, and has not been cleaned once. I throw out these facts that you may see the simple result from this manner of setting, and I shall leave to parties more versed in chemical affairs than I, to give a reason why such results are obtained. I will go still further and state that the Yonkers works, after they had run one bench three months, and experimented very carefully in regard to that bench, as compared with the old works, decided to

take down other benches that were nearly new and in good order, and reconstruct them on this plan, believing that they would save the expense of reconstruction (over $1,500) in three months' time. The result has proved that to be the case. The cost of building a bench of six retorts by this process, commencing at the foundation, is not as great as by the old. You notice in this two stand pipes, and in the old you have six.

To change a bench of the old retorts to this new setting is a matter of very small moment. I feel, gentlemen, that any improvement, coming from what quarter it may, that will add to the quantity of gas, keeping quality the same as it is now, is deserving of investigation. I should be glad to answer any questions from any one.

In reply to questions Mr. Condict made the following statements;

We work by the same heat as by the old process. We find no obstruction whatever in the rear opening; the opening is from 12 to 14 inches in size, and has never been closed.

The

We use the same exhauster as in the old works. entire works, aside from the setting of retorts, is the same as the old process.

We use the long ton in making our estimates.

We have made as high as 14,000 feet, during the entire nine months, averaged 12,000 feet of 17 candle gas ; without any enriching coal, and without a pound of coal (excepting Westmoreland) other than the two tons referred to of Murphy Run coal.

I will mention one fact-that the Yonkers works have used only Clover Hill coal (which you know is inferior to Westmoreland) that cost them on the docks $6.50 a ton, and their gas to-day is a little too rich. They get over 11,000 feet from this Clover Hill coal, while we obtained 12,000 feet from Westmoreland.

A simple way to overcome the stoppage is to introduce a little jet of steam in the hydraulic pipe or stand