10 farmers' bulletin 603. 



There are two methods of attacking the problems of replenishing 

 a bath and of correcting its strength — (1) method by weight and (2) 

 method by volume. 



The method by weight. — This method bases all calculations upon 

 the weight of white arsenic which actually is in the vat and the 

 weight which ought to be in the vat. Table 1 ^ gives the weight of 

 white ar.senic which is actually present in baths of various volumes 

 and of varying percentages of arsenious oxid. 



When the quantity of bath in the vat lies outside the range of the 

 figures given in Table 1 it will only be necessary to multiply or to 

 divide by 2. For example, if the bath amounts to 750 gallons it must 

 evidently hold only half as much arsenic as if it amounted to 1,500 

 gallons. If, on the other hand, it is desired to more accurately 

 employ figures which lie between those given in the table, either for 

 volume of bath or for percentage or weight of arsenic, it is only 

 necessary mentally to split the difference between the figures actually 

 given. 



The manner in which Table 1 is used may be illustrated as follows : 



Suppose one needs to replenish and correct a bath which is contained in a 

 vat holding 1,500 gallons to the full water line. He finds that he has in the 

 vat 1,050 gallons of bath which his analyst informs him contains 0.14 per 

 cent actual arsenious oxid. Looking up these figures in the table, he finds 

 that they indicate 12^ pounds of arsenious oxid in the vat. What he wants is 

 a vat filled with solution of proper dipping strength, we will say, of the low- 

 strength formula. Now, the low-strength fornnila calls for 0.19 per cent 

 actual arsenious oxid, and, as before stated, his vat holds 1,500 gallons to the* 

 full water line. Lodging up these figures in the table, he finds that his vat 

 when filled with solution of proi>er strength must contain 23f pounds of 

 arsenious oxid. Therefore, in filling his vat to the full water line he must 

 introduce 23f less V2\ pounds of white arsenic, or Hi ix>unds. 



Having found from Table 1 the weight of white arsenic necessary 

 to add to the vat, subsequent procedure depends upon the kind of 

 dip used. In the case of boiled dip prepared on the spot, it is 

 simply necessary to weigh out the proper amount of arsenic and to 

 boil it with the corresponding amount of sodium c^ubonate, water, 

 etc. In case the low-strength boiled arsenic stock is to be employed, 

 it is necessary to remember that it carries 1 pound of arsenious 

 oxid in every 3| gallons. Therefore, multiply the number of pounds 

 of white ai'senic needed by 3^ in order to find the number of gallons 

 of low-strength boiled arsenic stock io be added. In «ise of the 

 S-B ar.senic stock, there is present 2 pounds of arsenious oxid in 

 every gallon. Therefore, divide the number of pounds of white 

 arsenic desired by 2 in order to obtain (he corresponding number of 

 gallons of S-B arsenic stock. 



The high-strength lM)ilo(l ai'senic stock, of course, carries 1 ]wnnd 

 of white arsenic in each 'J.t gallon.s. 



1 Credit for this form of table Ib due to Dr. CJ. A. Hundley, veterinary Inspector In thta 

 bureau. 



