MESSRS EDITORS—Permit me to lay before your readers a process for the prevention of incrustations in the boilers of oceangoing steamships The incrustations are composed of the carbonates, sulphates and muriates of lime, magnesia, and soda ; the two first being the most abundant, contrary to what from an a priori view of the composition of seawater might be anticipated Any incrustations which I have examined contain but a very minute portion of muriate of soda, which, according to the analysis of Murray and Vogel, constitutes at least fourfifths of the solid ingredients of seawater, this salt being almost entirely got rid of bythe mechanical process of blowing " through," resorted to by engineers for the purpose of keeping their boilers clean My experiments have been directed to the discovery of a substance which, when introduced into the boiler, would communicate to the whole mass of solid matter contained in seawater, a fluidity equal to that of the muriate of soda, and I think that this is effected by the employment of masses of metallic antimony These being placed in the boiler, the action of the muriatic acid contained in the seawater forms muriate of antimony, which imparts to the other salts with which it comes in contact the necessary degree of solvency to permit of the whole mass being got rid of by the ordinary process of " blowingoff " above mentioned Analogous instances of increased solubility by amalgamation and admixture are common in chemistry I may cite the wellknown fusible metal compound of bismuth, lead and tin, none of which singly melt at a lower heat than 442 Fah, whilst in conjunction they are soluble at a point at or under that of boiling water I am led to believe that antimony possesses the power of imparting increased solvency to some of the substances with which it comes in contact by a consideration of the properties of the tartrate of antimony and potass (common tartar emetic) Tartrate of potass by itself 6 so slightly soluble in water as to have led to the employment of tartaric acid as the special test for the detection of the various combinations of potassa, but as it exists in the abovenamed preparation with antimony we have a salt of familiar solubility I think it also not unreasonable to suppose that owing to the contact of the antimony with the metal of the boiler, aided by the liberation of the muriatic acid, sufficient electricity may be generated to assist in the prevention of the adhesion of the earthy particles, a view which is substantiated by the discovery of Davy, who found that a piece of zinc the size of a pea inserted into the coppersheathing of a vessel was fully equal to the preservation of forty or fifty square inches of the latter metal from corrosion I have been engaged for some years in experiments bearing on the prevention of incrustations in boilers, and have found that in models the employment of antimony is allsufficient for the purpose Soon after its introduction into the boiler, the presence of antimonial salts in the water can be demonstrated by the usual reagents, and I have found it quite possible to keep a small boiler in which very strong sea water was constantly boiling, evaporating and digesting perfectly clean and lustrous interiorly for an indefinite length of time, without resorting to "blowing through" one tenth part as eften as is usual at sea I have made no experiments on the large scale with sufficient material to enable one to arrive at any definite conclusion, and I am aware that my experiments are in consequence defective, as several processes for the same purpose which have been apparently correct in theory, and have answered well with the model, have been found worthless when applied to large boilers ; but I have been induced to give the results of my researches so far as they have gone, as some of my notes have ' been stolen, and I am apprehensive of the use which may be made of them I am also in Shopes that the publication of my remarks may lead to a trial which may end in some discovery by which the desired result may be attained HENRY FISHER, M D 121 Bleecker st, New York, March, 1858 [This is an important communication It suggests the use of a new substance to prevent incrustations in marine boilers, which, if it answers the purpose, must be far superior to astringent matters which are sometimes employed, as it will not injure the iron like these In sea steamers, there is no choice of water ; they must use the salt brine of "old Ocean" This is so highly charged with depositing saline matter, that a crust of about oneeighth of an inch thick is formed in a boiler during a voyage between New York and Liverpool As this scale on the inside of the boiler is a nonconductor—in comparison with the metal—it follows that a great waste of fuel is caused by its formation It also tends to injure the metal of the boiler, especially the flue tubes, and much labor is expended to remove it at the end of every trip Any simple, cheap, and efficient remedy for these evils is therefore an object of great consequence