-----------------------------+--------------+------------------ -- | Common News.| Good Printings. -----------------------------+---------------+----------------- Weekly output of paper, say | 600 tons | 250 tons Mechanical wood pulp, moist, | | 50 per cent. dry | 800 " | Nil. Chemical wood pulp, dry | 200 " | 150 tons Esparto | Nil. | 200 " Soda ash | Nil. | 16 " Coal | 600 tons | 800 " Lime | Nil. | 45 " China clay | 60 tons | 25 " Bleach | Nil. | 30 " Alum, rosin, and chemicals | 20 tons | 20 " Water, per ton paper | 8,000 gallons| 40,000 gallons -----------------------------+---------------+----------------- _The Sarco Combustion Recorder._--This instrument is a device which automatically records the percentage of carbonic acid gas in the waste gases from boiler furnaces. The flue gases are analysed at frequent and regular intervals, and the results of the analysis can be seen on a chart immediately, so that it is possible to determine the effect of an alteration in the firing of the boilers within two minutes of its taking place. The apparatus is rather complicated, but the principle upon which it is based is simple. Measured quantities of the flue gases are drawn into graduated glass tubes and brought into contact with strong caustic soda solution, which absorbs all the carbonic acid gas. The remaining gases not absorbed by the caustic soda are automatically measured and the percentage of carbonic acid gas registered on the chart. The use of suitable boiler feed-water is also an important factor in modern steam-raising plant. The hot condensed water from the paper machine drying cylinders, and exhaust steam from the engines and steam-pipes, is returned to the stoke-hole to be utilised in heating up the cold water which has been previously softened by chemical treatment. [Illustration: FIG. 55.--Conventional Diagram of a Water Softening Plant. A. Water supply. B. Regulating tank. C. Lime mixer. D. Soda tank. E. Settling tank and filter. F. Outlet for softened water. ] _Water Softening._--The water softeners available on the market are numerous, and as each possesses special advantages of its own, it would be almost invidious to select any one for particular notice.