The apparatus used in working the process consists of a tower still, containing a number of superposed trays about 3 or 4 inches apart, with a lipped hole through the bottom of each at the side. The trays are so placed in the tower that the holes are at alternate sides. The liquor passes into the top of the still, and zigzags down through the series of trays, as in an ordinary Coffey still. The bottom tray differs from the rest; being much deeper, and having holes through it connecting it with the furnace, which is set immediately below it. The products of combustion of the fuel are caused to pass from the furnace up through the holes in the trays in the still, and, together with the gases evolved from the liquor, are directed into the saturator, where the sulphate of ammonia is obtained either in solution or in the crystalline state. Where the process is at present being worked, an exhauster is used to draw the furnace gases through the still; but it might be advantageous to use a blower. A small plant has been put in action at the gas works in Kilkenny and another on a larger scale, and differing somewhat in detail, here in Glasgow at the Alum and Ammonia Company's works, where the liquor from the Tradeston Gas Works is converted. The trials on a working scale have only been made at both places within the past ten days; and, so far, nothing has appeared against the principle, though in certain of the details of construction some alterations are being made to improve it. The extra yield of salt from a given quantity of acid obtained in the experiments has been proved in practice, as also the absorption of the sulphureted hydrogen. The other day, while ammoniacal liquor of about 9 oz. strength was being run at the rate of 70 gallons per hour through the still, 5 feet in diameter and 10 feet high, containing seventeen trays, no smell of sulphureted hydrogen was perceptible from the waste gases from the saturator, although on applying lead paper a slight trace of this impurity was noticeable, and it may be stated that the gases were being delivered at the ground level, where there was no difficulty in testing them. In the Glasgow apparatus we have found it advisable to enlarge the pipe leading the gases into the saturator, as the volume of these is much greater than would be the case in the ordinary method of working. Further experience will probably indicate the desirability of increasing the height of the still, which, being only 10 feet, is not more than half the height that Coffey stills are ordinarily made. * * * * * THE ANALYSIS OF URINE. INTRODUCTION.