123 



erage of the contents of the package; it is recommended 

 that, where conditions permit, one barrel in every 10 be 

 sampled. 



2. All samples should be passed through a sieve having 

 20 meshes per linear in., in order to break up lumps and 

 remove foreign material; this is also a very effective 

 method for mixing them together in order to obtain an 

 average. For determining the characteristics of a ship- 

 ment of cement, the individual samples may be mixed 

 and the average tested; where time will permit, however, 

 it is recommended that they be tested separately. 



3. Method of Sampling: Cement in barrels should be 

 sampled through a hole made in the center of one of the 

 staves, midway between the heads, or in the head, by 

 means of an auger or a sampling iron similar to that used 

 by sugar inspectors. If in bags, it should be taken from 

 surface to center. 



Chemical Analysis. 



4. Method: As a method to be followed for the analysis 

 of cement, that proposed by the Committe on Uniformity 

 in the Analysis of Materials for the Portland Cement In- 

 dustry, of the New York Section of the Society for Chemi- 

 cal Industry, and published in the Journal of the Society 

 for January 15, 1902, is recommended. 



Specific Gravity. 



5. Apparatus and Method: The determination of spe- 

 cific gravity is most conveniently made with Le Chate- 

 lier's apparatus. This consists of a flask (D), Fig. 1, of 

 120 cu. cm. (7.32 cu. in.) capacity, the neck of which is 

 about 20 cm. (7.87 in.) long; in the middle of this neck 

 is a Inilb (C), above and below which are two marks (/') 

 and (E) ; the volume between these marks is 20 cu. cm. 

 (1.22 cu. in.). The neck has a diameter of about 9 mm. 

 (0.35 in.), and is graduated into tenths of cubic centi- 

 meters above the mark (/'). 



6. Benzine (62 Baume naphtha), or kerosene free, from 

 water, should be used in making the determination. 



7. The specific gravity can be determined in two ways: 

 (1) The flask is filled with either of these liquids to the 



lower mark </,') ami til gr. (_'.:.'." ox.) of powder, previ- 

 ously dried at 100 C. (212 F.) and cooled to the tem- 

 perature of the liquid, is gradually introduced through 

 the funnel (/*) [the stem of which extends into tlu> llask 

 to the top of the bulb (C)], until the upper mark (F) is 

 reached. The difference in weight between the cement 



