302 MODERN BUTTER MAKING. 



The difference here is due only to the difference in 

 the graduation of the bottle, the size of neck and 

 the grams used. It will be noticed that the space 

 between the markings on the bottle, Pig. Ill, are 

 about three times as close as the markings on bottle, 

 Fig. II. This closeness of graduations increases er- 

 rors in reading, by three. The closer the markings 

 of spaces occupying 1 per Cent on the reading, the 

 greater are the chances of errors arising through not 

 being able to get a perfectly correct reading. From 

 this analysis it seems that the bottle shown in Fig. 

 III. is the most difficult to read correctly. The safest 

 way to read this bottle is to read from the extreme 

 bottom, a, to the extreme top, c, of the fat column, 

 and subtract on the average about 2 per cent from 

 the reading. 1. per cent occupies 1/18 inch on the 

 50 per cent, 6 inch, 9 gram bottle, Pig. Ill, and 1. 

 per cent occupies 1/6 inch on the 30 per cent, 9 inch, 

 18 gram bottle. 



81. Comparing a 55 per cent, 9 inch, Fig, IV., 18 

 gram cream test bottle with a 50 per cent, 6 inch, 

 Fig. Ill, and a 30 per cent, 9 inch. Fig. II, bottle. 



Pig. IV, 55 per cent, 9 inch, 18 gram cream test 

 bottle is graduated into ^^ per cent divisions; each 

 division measuring in width 1/23 of an inch. Each 

 1/23 inch on the neck of the bottle means .5 per cent 

 fat. 1 per cent of fat occupies about 1/12 inch space. 

 In bottle shown in Pig. II, 1 per cent occupies 1/6 of 

 an inch space. The per cent spaces, on a 30 per cent, 

 9 inch cream bottle. Fig. II, are twice as wide as 

 those on the bottle shown in Pig. IV, and at the same 

 time represent the same per cent of fat. Any error 



