In order to be convinced that the purification of the water has been properly conducted, we try the water in the following manner. Take a sample of the purified water into a small tumbler, and add a few drops of a solution of oxalate of ammonia; this addition must neither immediately nor after some minutes cause a milky appearance of the water, but remain bright and clear. A white precipitate would indicate that not enough carbonate of soda had been added. A new sample is taken of the purified water and a solution of chloride of calcium added; a milky appearance, especially after heating, would show that too much carbonate of soda had been added. RESULTS OF THIS WATER PURIFICATION. 1. The boilers do not need to be cleaned during a whole season, as they remain entirely free from incrustation; it is only required to avoid a collection of soluble salts in the boiler, and therefore it is partly drawn off twice a week. 2. The iron is not touched by this purified water. The water does not froth and does not stop up valves. The fillings in the joints of pipes, etc., do not suffer so much, and therefore keep longer. 3. The steam is entirely free from sour gases. 4. The production of steam is easier and better. 5. A considerable saving of fuel can soon be perceived. 6. The cost of cleaning boilers from incrustation, and loss of time caused by cleaning, is entirely done with. Old incrustations, which could not be cleaned out before, get decomposed and break off in soft pieces. 7. The cost of this purification is covered sufficiently by the above advantages, and besides this, the method is cheaper and surer than any other. The chemical factory, Eisenbuettel, furnishes pure carbonate of soda in single packages, which exactly correspond with the quantity, stated by the analysis, of ten cubic meters of a certain water. The determination of the quantities of lime and carbonate of soda necessary for a certain kind of water, after sending in a sample, will be done without extra charge.--_Neue Zeitung fur Ruebenzucker Industrie_. * * * * * EDDYSTONE LIGHTHOUSE.