. Milk. Milk. 146 MILK dried. It is then filled with milk and weighed again. From the difference in weight between the milk and water the specific grav- ity is calculated. The glass stopper may have a thermometer attached which reaches into the fluid to be tested and records the temperature. When milk is tested the temperature of both milk and water should be 60° F. Very accurate results are obtained by the use of a Westphal balance (Fig. 39). This instrument consists of a beam to the end of which a plummet is hung and a glass cyhnder to hold the fluid to be tested. The beam is supported by a
. Milk. Milk. 146 MILK dried. It is then filled with milk and weighed again. From the difference in weight between the milk and water the specific grav- ity is calculated. The glass stopper may have a thermometer attached which reaches into the fluid to be tested and records the temperature. When milk is tested the temperature of both milk and water should be 60° F. Very accurate results are obtained by the use of a Westphal balance (Fig. 39). This instrument consists of a beam to the end of which a plummet is hung and a glass cyhnder to hold the fluid to be tested. The beam is supported by a cylindric stand and fastened to a cyhnder fitting closely inside the support. This inner cylinder carrying the beam is movable, so that the height of the beam can be ad- justed. The absolute weight of the plummet (Reimann's plum- met with thermometer) is 15 grams including the platinum wire, and it displaces 5 grams distilled water at 15° C. The beam is divided into ten parts, each one of which is indicated by a notch. There are four weights (riders) which are hung on the beam. The largest rider represents 5 grams, the next size , and the others and gram, respectively. To use the balance the pro- cedure is as follows: The plum- met is hung to the end of the beam and is immersed in distilled water contained in the cylinder. The largest rider is hung above the plummet. The balance is perfect when the plummet and twisted wire are covered with water and the metalhc point at the further end of the beam is in opposition. The exact place where the surface of the water reaches the wire is to be noted. After this pre- liminary observation the water is discarded and the milk placed in the cyhnder. The second largest rider is then placed on the beam and moved until perfect balance is established. This rider is then moved back into the nearest notch. The other riders are then placed one after the other on the beam and moved to the notch nearest the place where perfect balan
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Keywords: ., bookauthorheineman, bookcentury1900, bookdecade1910, bookyear1919
