194 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G. 



METHOD OF USING THE DISTILLING APPARATUS. 



556 Attach the water supply, which may be a Cistern or Cask placed four feet above the 

 Condenser, the connection being by Flexible Tube from the Tap of the Cistern ; the outflow 

 of water is to be conducted into a pail, the quantity used being regulated by the Cock in 

 the Cistern ; and the water having been found to flow through the Condenser in a con- 

 tinuous stream, the Gas Lamp should be connected also by means of Flexible Tube, with a 

 Gas Pipe, and lighted on the top of the Gauze. Where Gas is not obtainable, a large Spirit 

 Lamp can be used. 



To Test a Sample of Wine. Fill the Measure Flask with Wine to the highest mark, 

 adjusting the exact quantity by using the Pipette ; pour the measured Wine into the Still 

 Flask, rinsing out the Measure with a few drops of water which must be added to the Wine ; 

 the measure being quite clean, is placed upon the bracket, and adjusted to receive the 

 Distilled Wine Spirit; the Still Flask is then to be screwed tightly to the condenser, 

 interposing an Indiarubber Washer between the Flask and the metal shoulder of the Still 

 Pipe ; put the Lamp under the Still Flask, at first moderately burning, afterwards increase 

 the flame ; in a few minutes the Wine will boil, and the vaporised Spirit will begin to con- 

 dense, falling into the Measure. Repeated experiments have proved that with weak Wine, 

 such as contain under 26 per cent, of Proof Spirit, it is only necessary to distil over one- 

 half the bulk ; but stronger Wines, containing much extractive matter, require the 

 operation to be continued until two-thirds are distilled ; the Standard Measure is therefore 

 graduated at two-thirds as well as one-half. When the required point on the Measure is 

 obtained, the original measure of the Wine (up to the highest mark) is to be made up with 

 Water, then poured into the Trial Glass and stirred well, so that the Spirit and Water may 

 be perfectly mixed : with the Thermometer the temperature should be observed, the 

 strength being taken by Sikes' Hydrometer according to the usual tables. 



To insure extreme accuracy, it is necessary that the temperatures of the Wine before 

 distillation, and the Spirit and Water before taking the strength by the Hydrometer, should 

 be the same, that the two bulks may be identical. 



Accurate Balances and Weights, Specific Gravity Bottles, Test Jars, Graduated 

 Measuring Glasses, &c., &c., for use with the Distilling Apparatus. See sections 

 " Thermometers," " Hydrometers," and " Chemical Apparatus." 



557 Negretti and Zambia's Patent Strengthened Glass Hydrometer, fig. 557 

 Of all glass instruments required by the exigencies of Science, the Glass Hydro- 

 meter is the most delicate and fragile. Very many of these instruments are broken 

 in carriage, and very recently the Government of India requiring a large number 

 of Hydrometers for fiscal purposes, applied to Messrs. Negretti and Zambra for 

 assistance in procuring an Hydrometer which could be safely sent to the interior 

 of India. Messrs. Negretti and Zamba submitted some instruments, which so far 

 fulfilled the conditions required, that 20,000 of Messrs. Negretti and Zambra's 

 Patent Hydrometers were ordered and supplied. The novelty consists in insert- 

 ing an inner tube down the stem, and reaching to the bottom, and there being 

 fastened securely to the neck of the lower bulb ; it will be seen that by these means 

 the weight of the instrument is supported from the bottom, and not at the juncture 

 of the stem with the large bulb, where usually the breakage of the old form of 

 Glass Hydrometers 'took place. 



Any form of Hydrometer described in the preceding pages can be constructed 

 with Negretti and Zambra's improvement to order at a slightly increased expense. 



