We have tried many experiments to produce hydrochloric acid in the producers, with the hope of thereby increasing the yield of ammonia, as it is well known that ammonium chloride vapor, although it consists of a mixture of ammonia gas and hydrochloric acid gas, is not at all dissociated at temperatures at which the dissociation of ammonia alone has already taken place to a considerable extent.

I had also hoped that I might in this way produce the acid necessary to combine with the ammonia at very small cost. For this purpose we moistened the fuel used with concentrated brine, and also with the waste liquors from the ammonia soda manufacture, consisting mainly of chloride of calcium; and we also introduced with the fuel balls made by mixing very concentrated chloride of calcium solution with clay, which allowed us to produce a larger quantity of hydrochloric acid in the producer than by the other methods.

We did in this way succeed in producing hydrochloric acid sometimes less and sometimes more than was necessary to combine with the ammonia, but we did not succeed in producing with regularity the exact amount of acid necessary to neutralize the ammonia. When the ammonia was in excess, we had therefore to use sulphuric acid as before to absorb this excess, and we were never certain that sometimes the hydrochloric acid might not be in excess, which would have necessitated to construct the whole plant so that it could have resisted the action of weak hydrochloric acid - a difficulty which I have not ventured to attack. The yield of ammonia was not in any case increased by the presence of the hydrochloric acid. This explains itself if we consider that there is only a very small amount of ammonia and hydrochloric acid diffused through a very large volume of other gases, so that the very peculiar protective action which the hydrochloric acid does exercise in retarding the dissociation of ammonia in ammonium chloride vapor, where an atom of ammonia is always in contact with an atom of hydrochloric acid, will be diminished almost to zero in such a dilute gas where the atoms of hydrochloric acid and ammonia will only rarely come into immediate contact with each other.

When we burnt coke by a mixture of air and steam in presence of a large excess of hydrochloric acid, the yield of ammonia certainly was thereby considerably increased, but such a large excess cannot be used on an industrial scale. I have therefore for the present to rest satisfied with obtaining only half the nitrogen contained in the fuel in the form of ammonia.

The enormous consumption of fuel in this country - amounting to no less than 150 million tons per annum - would at this rate yield as much as five million tons of sulphate of ammonia a year, so that if only one-tenth of this fuel would be treated by the process, England alone could supply the whole of the nitrogenous compounds, sulphate of ammonia, and nitrate of soda at present consumed by the Old World. As the process is especially profitable for large consumers of fuel situated in districts where fuel is cheap, it seems to me particularly suitable to be adopted in this country. It promises to give England the privilege of supplying the Old World with this all-important fertilizer, and while yielding a fair profit to the invested capital and finding employment for a considerable number of men, to make us, last not least, independent of the New World for our supply of so indispensable a commodity.

Before leaving my subject, I will, if you will allow me, give you in a few words a description of two other inventions which have been the outcome of this research. While looking one day at the beautiful, almost colorless, flame of the producer gas burning under one of our boilers, it occurred to me that a gas so rich in hydrogen might be turned to better use, and that it might be possible to convert it direct into electricity by means of a gas battery.

You all know that Lord Justice Grove showed, now fifty years ago, that two strips of platinum partly immersed in dilute sulphuric acid, one of which is in contact with hydrogen and the other with oxygen, produce electricity. I will not detain you with the many and varied forms of gas batteries which Dr. Carl Langer (to whom I intrusted this investigation) has made and tried during the last four years, in order to arrive at the construction of a gas battery which would give a practical result, but I will call your attention to the battery before me on the table, which is the last result of our extended labors in this direction, and which we hope will mark a great step in advance in the economic production of electricity.

The distinguishing feature of this battery is that the electrolyte is not employed as a mobile liquid, but in a quasi-solid form, and it is, therefore, named dry gas battery. It consists of a number of elements, which are formed of a porous diaphragm of a non-conducting material (in this instance plaster of Paris), which is impregnated with dilute sulphuric acid. Both sides of this diaphragm are covered with very fine platinum leaf perforated with very numerous small holes, and over this a thin film of platinum black. Both these coatings are in contact with frameworks of lead and antimony, insulated one from the other, which conduct the electricity to the poles of the battery.

A number of these elements are placed side by side, with non-conducting frames intervening, so as to form chambers through which the hydrogen gas is passed along one side of the element and air along the other.

This peculiar construction allows us to get a very large amount of duty from a very small amount of platinum. One of the batteries before you, consisting of seven elements, with a total effective surface of half a square meter, contains 2½ grammes of platinum leaf and 7 grammes of platinum black, a total of 9½ grammes of platinum, and produces a current of 2 amperes and 5 volts, or 10 watts, when the outer resistance is properly adjusted. This current is equal to nearly 50 per cent. of the total energy obtainable from the hydrogen absorbed in the battery.