BULLETIN" 56, U. S. DEPARTMENT OF AGEICULTURE. 



use and gives the percentage of water direct without multiplying by 

 two, which must be done in employing the one commonl}'- used. 



Usually a small quantity of oil is carried over into the measuring 

 cyliQder and collects on the surface of the water, so that the readiQgs 

 should be made at the bottom of the meniscus between the oil and 

 the water, as shown in figure 4. After the test has been made the 



graduate should be 

 emptied and wiped 

 dry. A cleaner can 

 be made by doubling 

 and twisting a wire 

 which has a fair de- 

 gree of stiffness and 

 wrapping absorbent 

 cotton or waste around 

 the end above the 

 hooks. The ends of 

 the wire should be 

 turned around in a half 

 circle, so as to make a 

 'convenient hook to 

 catch the cotton or 

 waste, as illustrated in 

 figure 5. 



OIL USED IN MAKING 

 THE TEST. 



The oil to be used 

 should be the same as 

 that specified in Circu- 

 lar No. 72 of the Bu- 

 reau of Plant Industry, 

 in which it is described 

 in part as follows: 



In making tests a good 

 grade of mineral engine oil 

 should be used. The oil 

 must be free fi'om water, 

 should have a flashing point 



Fig. 3.— Sectional view of the Urown-Duvel moisture tester, showing 

 the various parts connected for use. A , Distillation flask in posi- 

 tion, three-eighths of an inch aljove the wre gauze ; B, distillation 

 fla-sk in the wooden rack used only during the filling. 



in open cup of approximately 200° to 205° C. (392° to 401° F.), and preferably a 

 VLScosity between 10 and 15 (Engler; at 20° C. (08° F.). After the tests are com- 

 pleted and while the oil is still hot, empty the contents of the flasks into a strainer 

 to recover the oil, which can be used repeatedly. A funnel strainer fitted to the 

 mouth of a 3 or 4 gallon milk can is serviceable and inexpensive. 



The funnel strainer mentioned is shown in figure 6. There should 

 be a small quantity of absorbent cotton placed in the bottom of this 

 strainer, so that only the oil can collect in the can beneath. 



