Evaporating Sugar—Bessemer's Process —The claims of two patents for improve ments in the manufacture of sugar, were pub lished in the last number of the " Scientific American. The patentee," Henry Bessemer, has long been favorably known in London, in connection with the refining of sugar. Some enquiries having been made of us since last week, respecting the alledged improvements, we will present all the information of which we are in possession at present. Hitherto all sugar has been boiled to expel the moisture, and leave it fit for crystalliza-llization. To boil sugar under a high heat completely discolors it. and previous to 1813, when Mr. Howard invented the vacuum pan to boil the sugar under a low heat, it was al most impossible to produce white sugar at all. The vacuum pan and the charcoal filter, in vented in France by Mm. Derome & Cail, in 1824, produced two revolutions in the manu facture of sugar, and it is asserted by Mr. Bessemer's admirers that his new improve ments will produce another revolution. By the new process the boiling of the su gar juice is dispensed with, the water is dri ven off the juice by bringing it in contact with currents of dry hot air blown in upon it as stated in the claim. The hot air is made to sweep over the surface of the fluid which is taken up on revolving metal plates sur rounding a hollow perforated cylinder. By this simple method it is said white syrups are concentrated without producing any discolo ration at all. The air is heated for this pur pose by being driven by a blower through tubes passing through an oven or furnace.— The second patent claim is for an improved filter. Crude sugars are of an ugly dark brown color, which is due to an external coating of molasses, which surrounds the crys tals of the sugar. This crude sugar in an al most fluid state, is placed in a machine and spread in a thin sheet in a circular table of wire gauze. A partial vacuum is formed un derneath by an air pump, and the wire gauze table rotates under a series of fine jets of water, which pass through the sugar with great velocity. This washes off all the molasses, leaving a pure and nearly white su gar. These operations are said to be perform ed with extraordinary facility and in an in credibly short space of time. Sugar boiling, refining, &c, are practical arts, that is to say, any departure from old practices can only be detarmined as an improvement by a fair trial, nothing else can decide the question.— Opinions, however, based upon experience, may be given, and with respect to the drying of sugar with hot air, we think well of it, we believe that it will operate well, it rightly conducted. MOUNTAINS IN THE SEA.—Capt. Denham, F. R. S. of the British Navy, while on a passage from Rio de Janeiro to the Cape of Good Hope took deep sea soundings of the great depth of 8J miles. In the "London Times" it is stated that soon afterwards he sounded igain in only 19 fathoms, on an extended co ral bank, thus showing that there are some very high submarine mountains in the ocean, which for the practical benefit of man as a commercial being it is of more importance to know, than the height of the mountains of the moon. It shows the necessity and im portance of acquiring a thorough knowledge af the configuration of the bottom of the seas and oceans. There ought to be hydrographic maps of all the seas and oceans, and all mari time nations should join in this great work. Something has already been done by our na vy, but a great work is still before us. What has been done will be found by our readers in the excellent Reports of Lieut. Maury, of the National Observatory. At the present moment the British have two vessels, the Herald and Torch, on a sur veying expedition on the Pacific, and particu lar instructions have been given to them to obtain deep sea soundings. They have disco vered two coralme banks, extending 80 miles, suddenly jumping from 200 fathoms, to no bot tom at all (beyond the lead) and then to 19 fathoms. The temperature o f the sea a 11,500 fathoms was 40 , where at the surface it was 90 . The temperature at the bottom, how ever deep the soundings, was never below 40 . The sun's rays were traced to have pe netrated to 66 fathoms. A survey was made of the coraline banks spoken of, and the Herald was at anchor in the middle of the ocean for a week to the ut ter astonishment of some ships whose tracks lay in that direction.