No. VIII. TECHNOLOGY.—PART V. FILTRATION AND CONCENTRATION OF THE JUICE. After leaving the carbonatation pans, the beet root juice, retaining still a certain proportion of both organic and inorganic impurities,isruninto a tank or reservoir, from which it is conveyed into large filters, filled with granulated bone-black. These filters are upright cylindrical vessels, made of boiler plate, generally from 12 to 15 feet high, with an internal diameter of from 39 to 40 inches. Several filters are always placed in a row, in close proximity to one another, forming what is called a filter battery. The following figure is a section through one of the filters in a such a battery. M is a cover, fitting very tightly on the top, through which the bone black is introduced. N is a manhole for drawing out the spent bone black, and also for admitting a sieve, covered by a cloth spread carefully over it, which is introduced into the bottom of the filter before the bone black is admitted. S is a wide pipe for the introduc tion of steam, pure water, beet root juice, and sirups into the filter; this is effected by means of the pipes, FE.DC, which are in connection with S, through which the passage of either of these fluids is regulated at will by means of special cocks. In order to preclude the possibility of mistakes beingmade by the workmen in the handling of these cocks, the pipes are superposed in the order of the density of the substances which are to be run through them, thus the steam pipe, F, is the lowest, next comes the clear water pipe, E, next that for the carbonatated juice, D, and uppermost of all, the pipe for conveying sirups, C. The steam pipe, F, is connected with the other three by means of a smaller pipe, in order to permit of their being occasionally cleaned by blowing steam through them. The reservoir for carbonatated juice is placed above the top of the filters; the higher the better, as it increases the hydraulic pressure, and forces the juice through the bone black with greater energy. The pipe, S, is also fitted with a small connecting pipe, L, through which the air escapes from the filter as it is gradually filling with liquid The juice, after having traversed 309 fftom top to bottom the whole body of bone black in the filter, is not allowed to run out at the bottom through the pipes W T; the cook, V, being kept closed so as to force it to ascend through the upright pipe, IT, from whence it is allowed to flow out through the open cock, H. This arrangement prevents a filter from ever running dry, as it will necessarily always remain full of juice to the level of H. The juice is received in a moveble funnel, T, which fits on the upright pipes, B and Q. If juice is being run through the filter, the funnel is placed on R, and is thus conveyed either directly to a tank, to a monte-jus, or to the evaporating pans, according to the disposition of the works. If sirup is being passed through the filter, the funnel is placed on Q and run to the concentrating pans, either directly or through a spe-icial monte-jus. When not in use, the top orifices of the pipes, E and Q, must always be carefully closed by metallic plugs. The accidental introduction of foreign substances into these pipes would cause very considerable trouble, loss of time, and expense. As in some cases it is flecessary to filter the Same solution twice over, a communication is often established between contiguous filtej by means of a special system of pipes and cocks. In our figure, V is used for running water into the pipe T, which carries it off as waste, or which conveys it to the bone black department, where it is used in. the process of fermentation, which we shall describe in due time. Filtration of the whole of the products undergoing the processes of man-ufacturetakes place nor-mally twice before crystallized sugar is produced from it. The first filtration is that of the carbonated juice; the second A this juice, after it has been subjected to evaporation, until it has reached the consistence of a thin sirup.. The working,of the filters in a battery being simultaneous for both juice and sirup, and to a certain extent combined, the same filters being first used for sirups, and subsequently for juice, we shall reserve our account of the modus operandi of filtration in general until we shall treat of the purification of sirups. After leaving the filters, the clear juice is conveyed to the evaporating pans, where it is reduced to a certain degree of consistentency, sirup, after which it has to be filtered a ssecond time, as we have already said. Evaporating pans in the olden times, were simple contrivances, and consisted in open boilers, either heated by the direct action of fire or by steam passing through double bottoms, or coil pipes. Some small sugar factories still use this latter system, which is wasteful in fuel and makes sugar of a more inferior quality than is done by the more perfect appliances of our day, known as -the triple effect vacuum pans. It would be tedious and unprofitable for us to sketch the history of the gradual progress in the perfection of vacuum pans, from the primitive Eillieux double effect pan to the more perfect triple effects now in use. We shall consequently limit ourselves here to the description of one of the best known, Eoberts pan, which, if well understood, will permit the reader to readily comprehend the working of all others, no matter what modifications or improvements they may present. Let us add, in this respect, that the original Eobert vacuum pan is hardly to be found in any manufactory unless it has been more or less altered in some details of its construction. Before explaining the use and advantages of the vacuum pan, we give a description of its various parts, which will facilitate our task. Pig. 1 is a side view of the whole apparatus. The three pans, or bodies, are marked I, II, III, the three intermediate vapor columns are numbered 1, 2, 3. A is the pipe which carries the juice into the first body. B C is a pipe which carries the juice from the first body to the second, and Q F, another which conveys it from the second to the third body, from whence the pipe, F, takes it to the monte-jus, Gt. H is a pipe through which the pans can be entirely emptied. I is a pipe communicating a vacuum from the condenser to the monte-jus. K is a pipe and valve for introducing the steam for heating into the first body. is a pipe for running off condensed water. L M is a pipe for conveying spent steam and condensed water to the condenser, N. 0 is the injection pipe of the, condenser. Q is the outlet for the hot water of condensation. P is a glass indicator for the hight of the juice in the pan. E is the apparatus for sampling, in order to lefirn. the density of the juice. S represents the glass bulls-eye for observing the progress of ebullition. T is a small funnel for the introduction of melted fat to arrest too violent ebullition. T is the small cock for admission of air. U is a thermometer indicating the temperature of the boiling j uice. V is a special barometer for low pressures for determining the degree of vacuum. X is an indicator for the water accidentally collected in the columns. Z is the pipe for running out the liquid which has found its way into the column. A man-hole is constructed in each body, but not figured in our cut, as it is placed at the back of the pan, as here exhibited. Fig. 2 shows a section through the last body of the above apparatus, so as to give a view of the internal arrangement of a vacuum pan. The lower portion of the body, III, shows the disposition of the tubes, around which the steam for heating the juice circulates. These tubes are inserted at both extremities into perforated end plates. The space above the top plate is the steam or vapor chest, where the vacuum is formed, and the steam of the boiling juice collects before being carried off. N is the condenser; 0 its injection pipe; M the exit pipe for heated condensation water, which is drawn off by an air pump; A is an upright pipe surrounded by an empty space, B, in which accidental water and liquid collects. In our next article we shall furnish a concise exposition of the theory and practice of the working of the triple-effect vacuum pan. The Spring Freshets. It is said that the spring floods of 1869 have been unusually destructive. On the Connecticut river, the height of the water has only been exceeded four times in the last seventy years. In Hartford, the water on April 23d, at noon, was 26 feet 8 inches above the low water mark. In 1854, the gage marked 30 feet. In Canada, the ice began to move out of the St. Lawrence on the night of April 22d, and the towns along the banks were seriously. damaged, houses and embankments having been swept away and several lives lost. In New York State, along Black river and the lower part of Lake Ontario, the floods were very violent. Factories, tanneries, dams, and flumes were carried off. Near Watertowh, a boom, restraining several acres of timber and flood wood, broke away from the chains, and carried off railroad bridged, mills, factories, furnaces, and machine shops. In the John Brown traW, the flood was caused By the breaking of a heavy dam, built to restraiathe water of a series of lakes, and forming a feeder to the New York canals. Near. Utica, the State dam, at a resersoir covering 500 acres, gave way, and the tood destroyed mills and other property valued at &10DJMQ. On iheHadsoft and Mohawk rivers, the inundations have beea very extensive, and the streets of Albany, Troy, and other cities in that vicinity, have been covered with water several feet deep.