912 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



I.— TABLE OF FREEZING-MIXTUEES (GUTHRIE). 



The temperatures obtained on mixing the salt with three to six times 

 its weight of ice in himi)s of the size of a pea downwards. 



Name. 



Sodium bromide 



Ammonium iodide 



Sodium iodide 



Copjjer clilinide 



Potassium iodide 



Sodium cbloiide 



Mapiiesium chloride .., 

 Strontium ihloi ido — 

 Ammouium sulphate. . 

 Ammonium bromide.. 



Ammonium nitrate 



Sodium nitrate 



Ammonium chloride . . 



Iron chloride 



Calcium nitrate 



Potassium bnmiide — 



Aluminium chloride 



Potassium chloride — 

 Potassium cluomate ... 



Barium chloride 



Strontium nitrate 



Magnesium sulphate... 



Zinc sulphate , 



Potassium nitrate 



Sodium carbonate 



Copper sulphate 



Iron sulphate - 



Potassium sidphate 



Potassium bichromate 



Barium nitrate 



Sodium sulphate 



Potassium chlorate 



Ammonia alum 



Mercury pcrchloride.. 

 Ammonium oxalate . . . 



NaBr 



NH^I ^ 



Nal 



CUCI2 



KI 



XaCl 



M^'Cl2 + CH.^0 



SrCli + Cn^O 



2NH4,S04 



^NIIjBr 



NU4NO3 



KaNOj 



NH4CI 



Fe Clj (commercial) 



Ca2NOj + 4n20 



KBr 



Al CI3 (in strong solution) 



XCl 



K.2Cr04 ... 



BaCla + aHjO 



Sr2N03 



MgSOa + THiO 



ZnSOj + THjO 



KNO, 



Ka^COj 



CuS04 + 5n20 



FeS04 + 7H20 



K.,S04 



K.^CrjOj 



Ba2N03 



Xa.,SO4 + 10H2O 



KCIO, 



Al,NH42SOi+12H20 



Hu-Clj 



N'H4COs 



28.0 

 27.0 

 28.0 

 20.5 

 24.5 

 22. 

 22.0 

 20.5 

 18.0 

 17.5 

 17.0 

 17.0 

 16.0 

 10.0 

 10.0 

 14.0 

 IJ. 



lao 



10.5 

 10.2 

 7.2 

 CO 

 5.3 

 5.0 

 3.0 

 2.2 

 2.0 

 1.7 

 1.5 

 1.0 

 0.9 

 0.7 

 0.7 

 0.4 

 0.2 

 0.2 



— 18.4 



— 16. G 



— 18.4 



— 15.7 



— 12.5 



— 7.6 



— 7.6 



— 4.9 



— 0.4 

 + 1.0 



1.4 



1.4 



3.2 



3.2 



3.2 



6.8 



8.0 



8.6 



13.1 



13.7 



20.3 



2L2 



23.5 



23.0 



26.6 



28.3 



28.4 



30. 



3a 2 



The temperatures here recorded are the lowest attainable for each 

 salt indei)endently of the temperature of the salt and its degree of crys- 

 talhydration. 



Professor Guthrie has determined that a cryohydrate undergoing solid- 

 ification may he considered physically as the homologne of a saturated salt- 

 solution in the act of boiling. Comparing the decomposition of a salt- 

 solution by the loss of heat with the decomposition by gain of heat 

 when such a solution boils, the following points may be noted : 



(1.) A solution poorer tlian that satu- 

 rated at a given temperature receives heat; 

 vapor is formed. 



(1.) A sohitiou poorer than the cryohy 

 drate loses heat ; ice is formed. 



(2.) This goes on until the proportion of 

 the cryohydrate is reached, the tempera- 

 ture falling. 



(3. ) The cryohydrate may he reached by 

 freezing out ice from a weaker solution, or 

 by any other withdrawal of water. 



(4.) When ice separates from a liquid, 

 it remains in contact with the liquid, and 

 endeavors to rcdissolve therein. 



(2.) This goes on until saturation is 

 reached, the temperature rising. 



(:J. ) Saturation may be reached by evap- 

 oration, boiling, or any other withdrawal 

 of water. 



(4.) Vapor separated from a liquid is re- 

 moved from the held of contention, unless 

 the liquid be enclosed with the vaiior. 



