testing for sulphuretted hydrogen and carbonic acid, as well as for ascertaining the specific gravity?

MR. PEARSON-No.

MR. GEGGIE-I think it can be used for that purpose also.

MR. PEARSON-I think not for testing for sulphuretted hydrogen. It will be useful in determining whether there would be carbonic acid in the gas, because the extra weight of gas, as shown by the test, would indicate its presence; but I have not heard that he has used it for the purpose of testing for sulphuretted hydrogen. He uses another apparatus for that purpose.

MR. SOMERVILLE-It seems to me the accuracy of the test depends upon the friction of the movement. If it should be a a little stiff it would not be accurate.

MR. PEARSON-The construction of it is such that it seems almost impossible for it to get stiff.

MR. SOMERVILLE-I suppose it should be kept in a dry room. MR. PEARSON-It is intended that the filter shall remove almost all of the moisture. Of course the presence of moisture would affect it. Mr. Lux states, from a number of tests made, he has ascertained that the very small quantity of moisture present is of very little account, and does not interfere with the accuracy of the balance. I think this is the fourth balance that Mr. Lux has made. He has made quite a number, and he claims that this is practically perfect.

MR. SOMERVILLE-Does it keep an automatic record of the specific gravity?

MR. PEARSON—He has another apparatus arranged in such a way as to keep a record, but this one is not of that type.

MR. DIALL-What is the price of it?

MR. PEARSON-I do not know. Mr. Lux claims that it will be especially useful in testing the gravity of furnace gases. Probably it will be more useful for that than for testing ordinary gas. You see that his claim is a very strong one. He claims that with this particular apparatus he can ascertain the specific gravity of gas within .001 part, which is near enough for anything we might need.

MR. MCMILLIN-I probably owe the Association an apology for asking the question, but I did not pay very close attention to the reading of the paper. May I ask if the object of the balance is chiefly to determine the quantity of carbonic acid.

MR. PEARSON-It is chiefly to determine the weight of the gas.

MR. MCMILLIN—Of what advantage would that be to us? MR. PEARSON-Probably you can tell that as well as anybody else.

MR. MCMILLIN-I do not see that it makes much difference whether a given quantity of gas weighs a pound or an ounce. I might care to know what it was composed of, but be indifferent as to its weight. That question, however, was with the view of leading to another, and that is-to determine the quantity of carbonic acid by testing the specific gravity, what would be the effect of running extremely high heats and decomposing a good deal of the marsh gas-thus removing a large per cent. of hydrogen, but leaving carbonic acid in it? Would it not have about the weight of a good gas, and still be of very poor quality? If that be so it would not be an absolute test as to whether there is a large per cent. of carbonic acid or not. This is certainly a very pretty piece of apparatus to look at, and my object is to ascertain whether it has any inherent utility.

On motion of Mr. Slater the thanks of the Association were voted to Mr. Pearson for his paper.

THE PRESIDENT-We will now listen to the reading of Mr. Somerville's paper.

DAILY EXPERIENCE AND OBSERVATIONS OF A GAS MANAGER.

By JAMES SOMerville.

In complying with the request of the Committee to read a paper before you on the above subject, I am well aware that I can find nothing that will be new to the majority of you. For my experience, from the nature of things, will be very similar to yours. Therefore, I will only be telling you something which you already know. But, no doubt, the Committee, in asking for

such a paper, had in view the younger members of our Association, and that our experience might be of some value to them. I will, therefore, ask that class among us to accompany me on one of my daily walks through the works, and we will relate our experience and make observations as we proceed.

The first place we will visit is the retort house, which is built on the stage principle, and although the plan is more expensive to build and maintain, yet it has so many advantages, that in the end I consider it to be the best and cheapest; and, no matter how small the works, I would advocate the adoption of this plan. One of its chief benefits is that you have ample space for the large modern gaseous furnace, which, in my opinion, is indispensable to the production of cheap gas; and if, as some of our sanguine friends predict, in a few years we will all be making fuel gas, then, with the two-story retort house the change to the new order of things can be more easily and cheaply made. You will perceive that the settings are very open, only braced in front and rear, which I have found quite sufficient. This allows ample space and time for the proper combustion of the furnace gases. I should like just here to lay some stress on this element of time in all our operations. My daily observation is that time is an important consideration in the condensing and purification of the gas. Nothing is more injurious to the gas than to suddenly rush it into a lower temperature. It requires time to cool slowly, time to get rid of its tar, time to purify.

You will observe that the heats are good, but not high. I find that there is no advantage in running high heats, that is, heats approaching a white. The gas from such heats is entirely. denuded of its light naphthas, and is in a poor condition to stand any change of temperature, but deposits the crystals of naphthaline the first opportunity, which occurs generally before or in the purifiers. I judge of a good heat when the lid is taken off and the retort presents a bright red, sparkling appearance, without a trace of smoke. The coke is curled up at the sides, and comes easily out when the rake is applied to it. I have observed that, when the heats are low from any cause, there is a corresponding decrease of ammonia; when the heats are good, the strength of the liquor increases. I am not prepared to say just why this should be, but the fact is well established in my mind that the

higher the heats the greater is the production of ammonia. It is possible that a greater amount of nitrogen may be taken from the coke during high heats and so cause the increase.

These self-sealing lids are only so in name. They do fairly well for the first year or so. But my experience is that beyond that period they are unable to stand the wear and tear of the retort house. The parts begin to wear out, perfect contact cannot be obtained, their efficiency is ended, and we have to fall back to the old lute. I confess I have given the subject of self-sealing lids much thought, but the difficulties appear to be insurmountable. They must be able to stand all changes of extreme temperature. Their efficiency must not be impaired by the wear and tear of the parts, and they must be able to make a perfectly air-tight joint every time they are shut, notwithstanding that they have to be handled by men who believe only in the existence of muscle.

We now come to what I call the hot scrubber. It is so hot you cannot keep your hand upon it. Here the gas takes a rest, as it were, and gets rid of all its heavy tar. You can hear it trickling down between the plates; but the light tars or oily naphthas still flow on with the gas which is gradually cooled. What tar is left is taken out by the Pelouze & Audouin condenser, which stands next to the ammoniacal liquor scrubber. I am aware that some object to placing the Pelouze at this point in the works, preferring to put it before the exhauster, where I have my hot scrubber. I think they are wrong; for it acts at that point too efficiently, if I may say so. It not only takes out the heavy tar, but the light naphthas also, and puts the gas in the same condition as if the naphthas had been burned up in the retort through extra high heats; and, moreover, the specific gravity of the tar at that point is so high that some will get through the Pelouze, not enough to help the gas any, but enough in the course of time to find its way to the liquor scrubber to seriously impede its efficiency and make it necessary to clean it out once or twice a year. This I never have to do; for no tar finds its way to the liquor scrubber nor into the liquor. This is important when making your own sulphate; for when tar gets into the scrubber it seems to neutralize in some way the action of the water on the gas. I do

not use fresh water in the scrubber. I have found it more effectual to use a mild liquor of about two or three-ounce strength. Gas has an aversion to cold water.

My experience with purifying material is that, when we used all oxide, it not only absorbed all the impurities, but a large proportion of the hydrocarbons also. I also attributed to its use an increase in the number of meters brought in for repairs. I had, therefore, to discontinue partially its use, and fall back on lime. I find that the center-seal, to perform its work properly, requires to be thoroughly scraped and cleaned once a year. I prefer the open drip, because it can be kept clean, and easily supplied with fresh water. I do not think it is right to pass the purified gas over foul water in the seal.

My observation of the daily working of the holders leads me to this conclusion. Whenever trouble has occurred it can invariably be traced to one source, viz., the weakness of the bottom curb. Let the bottom rollers get out of place, then the stability and safe working of the holder is destroyed. I have had a curious illustration of this fact. We have a holder 130 feet in diameter and only 16 feet in height. Why it was built with these dimensions I cannot tell. It is strongly trussed. The centre of gravity is nearer the top than the bottom, so that a little gale of wind invariably tipped it over. Indeed, I have seen it at right angles; one side jammed into the tank, the other high in the air. This occurred shortly after I took charge of the works. But the workmen were so used to it that it excited in them little surprise. But, as the cost of broken wheels and carriages was excessive, I resolved to see what could be done to make it work more steadily. As soon as we got into it I found, as you anticipate, that every roller was out of place, and the bottom curb badly bent in. I substituted wrought iron for cast wherever it could be done with the rollers, and put a heavy log chain or brace against them on the inside, fastened to the curb, and jammed the rollers tight against the guides. I filled it up again, and no one was more surprised than myself to see how steady the holder has worked ever since, now nearly ten years ago. It has given no trouble and is working every day. There are twelve columns to the holder; but, as for keeping it steady, it might as well be without them.