ADDENDA. 477 



P. 280. Back of rule (Fig. 53). To correct refractometer readings for 

 temperature. Place the cursor against the reading on the median 

 line, find the temperature above or below the normal (usually 

 40 C.) on the fan-shaped lines, and the correction (to be added 

 or subtracted) is read off on the scale on the cursor. 



P. 79. To correct lactometer readings for temperature, move the slide 

 till the reading is against the arrow, the corrected reading 

 will correspond with the temperature observed. Fahrenheit 

 degrees are on one side and Centigrade on the other. 



P, 187. Cream Analysis. To calculate solids not fat from total solids. 

 Find the percentage of total solids on the scale, and the per- 

 centage of solids not fat will correspond with this. Note that 

 the scales go different ways, the total solids scale reading from 

 right to left and the solids not fat from left to right. 



Similarly solids not fat can be calculated from fat by finding 

 the percentage on the fat scale. 



In the same way fat can be calculated from total solids and 

 total solids from fat. These two scales go the same way. 



P. 248. To calculate Polenske figures from Reichert-Wollny. Find the 

 corresponding figures, as above. This is useful in calculating 

 the percentage of coconut oil in adulterated butter from the 

 formula 



P P' 



Per cent, of coconut oil = - x 100, 

 144 



where P' = Polenske figure corresponding to Reichert-Wollny 

 -f- half the Polenske found. 



Example, R - W = 24 



P = 4-0 



Find Polenske corresponding to 24 + 4 X \ = 26, which is 

 found from the scale to be 2-23. Therefore, 



A 9'23 



Per cent, of coconut oil = - - - x 100. 

 14-4 



This calculation can be performed by the scales on the 

 front of the slide, thus : Place the cursor against 1 -77 

 (= 4 2-23) on the lower slide place 1-44 = (14-4^- 10) 

 against this, and the answer 1-23 is against 1. 



Per cent, of coconut oil = 1-23 x 100 -f- 10 = 12-3. 



P. 250. To calculate Polenske from Kirschner figure. Find the Kirschner 

 figure on the scale, and the Polenske will correspond to this. 

 If the Polenske figure actually found is 1-0 or higher than 

 that calculated the presence of coconut oil is established. 



P. 182. To calculate proteins from Aldehyde figure, find the Aldehyde 

 figure on the scale, and the percentage of proteins will corre- 

 spond with this. Similarly proteins can be calculated from 

 total nitrogen or vice versa. 



P. 188. There are other calculations in which the scale can be used. 

 A good approximation formula connecting the specific gravity 

 of cream and the percentage of fat is : 



32-5 0-91 lactometer degrees = fat. 



