50 



Frederick Guthrie on Salt Solutions 



Table XII. — Column (1) the weight in grammes of the pow- 

 dered CaCl 2 + 3 H 2 0, column (2) the weight in grammes of 

 the powdered ice or snow, columns (3) and (4) the respective 

 percentages of the two, column (5) the temperature. 



(1) 



W 



(3) 



(4) 



(5) 



CaCL.-KilL/), 



Snow or ice, 



Per cent., 



* Per cent., 



Temperature, 



grammes. 



grammes. 



CaClj+3H 2 



{snow or ice. 



Centigrade. 



*100 



33 snow 



75 



25 







-21 



100 



50 snow 



666 



333 



-28 



94 



60 ice 



61-5 



385 



-33 



*\75 



50 snow 



60 



40 



-32 



50 ice 



60 



40 



-32 



50 



75 snow 



40 



60 



-27 



r.5o 



*\50 



100 snow 



33-3 



66-6 



-24 



100 ice 



33-3 



666 



-24-5 



From this, especially from the examples marked *, it ap- 

 pears that snow and ice are of equal value as elements of crvo- 

 gens, and that the greatest cold is obtained on mixing 38*5 

 of ice or snow with 61'5 of the crystallized salt. This is the 

 ratio between CaCl a 3H 2 and 5*74 H 2 0, or 4(CaCl 2 3H 2 0) 

 and 23 H 2 or CaCl 2 and 8'74H 2 0. 



§ 106. B. Anhydrous CaCl 2 as Cryogen. — Freshly fused 

 CaCl 2 was finely powdered and mixed with finely crushed ice. 



Table XIII. — Columns (1) and (2) show the actual quantities, 

 in grammes, taken of CaCl 2 and ice respectively; columns (3) 

 and (4) show the percentages ; column (5) shows the lowest 

 temperature reached ; and the numbers in column (6) show 

 the temperature to which the mixture rose after all the ice was 

 melted in those cases where the proportion of ice was least. 



(1) 



(2) 



(3) 



(4) 



(5) 



(6) 



CaCl 2 , 

 grammes. 



Ice, 



grammes. 



CaCL,, 

 per cent. 



Ice, 

 per cent. 



Lowest 

 temp. 

 Cent, 



Rose to 

 temp. 

 Cent, 



50 



50 



500 



500 



o 



+33 





50 



75 



400 



600 



+ 10 to +18 



50 



90 



357 



64-3 



+ 4 „ +14 



50 



95 



34-5 



65-5 



+ 3 „ +11 



50 



100 



33-3 



667 



- 2 )t + 9 



50 



125 



28-6 



714 



-10 





33-3 



100 



25 



750 



-13 





25 



100 



200 



800 



-15 





20 



100 



167 



83-3 



-14 5 





166 



100 



142 



85-8 



-12 





20 



140 



125 



87-5 



-12 





