354 PEINCIPAL HENRY A. MIERS AND MISS FLORENCE ISAAC ON THE 



Remarks. 



The index rose from 1 -422974 at 53 to 1-435442 at 21 -5. A very dense shower 

 of /3-crystals occurred suddenly at 21 -5, the temperature rose to 25, and the 

 index fell to 1-432862. The temperature then fell again, and the index con- 

 tinued to fall, reaching 1-431870 at 22. The solution was now inoculated with 

 a and a transformation from /3 to a. took place immediately, the temperature 

 rising to 24 -5, with another dense shower. The index fell to 1-429680 at 

 24 -5. The temperature fell again, and from 24 -5 to 18 -5 the index-tempe- 

 rature curve coincides with the a-solubility curve, the index being 1 428092 at 

 18-5. 



The index rose from 1-426183 at 44 to 1-435739 at 21. A single /3-crystal 

 appeared at 21, followed at once by a shower of /3-crystals ; the temperature rose 

 to 24 and the index fell to 1-433061. The temperature then fell again and the 

 index also continued to fall, reaching 1-431969 at 20 -5. Here the temperature 

 suddenly rose spontaneously to 23, and the /3-crystals transformed to a. 



The index rose from 1-422675 at 48 to 1-433757 at 19 -5. /3-crystals Appeared 

 at 20 and a /3-shower occurred at 19 '5, the temperature rising to 20 and the 

 index falling to 1-432466. The temperature then fell again and the index con- 

 tinued to fall, reaching 1- 429780 at 13, corresponding to a point on the /3- 

 solubility curve. Inoculation with a caused another shower and transformation 

 from /3 to a, with rise of temperature from 13 to 16. The index at the same 

 time fell to 1-427694 at 16, corresponding to a point on the a-solubility curve. 



The index rose from 1-423177 at 46 to 1-434453 at 17 -9. A few small /3- 

 crystals appeared at 19 and a dense shower of ft at 17 -9. The temperature 

 rose to 21" and the index fell to 1-432168. The temperature then fell again and 

 the index continued to fall, reaching 1-431175 at 19; this corresponds to a 

 point, practically, on the /3-solubility curve. 



The index rose from 1-423478 at 42 -5 to 1-434354 at 15. At 15 a very dense 

 shower of /3-crystals occurred, the temperature rose to 19, the index falling to 

 1-431474. The temperature then fell again and the index continued to fall, 

 reaching 1-429978 at 13. After the shower the index-temperature curve coin- 

 cides with the /3-solubility curve, from 18 to 13. Two hours later, on inocu- 

 lating with a, the whole solution transformed from /3 to a, and the temperature 

 rose from 13 to 16. 



The index rose from 1-421872 at 45 to 1-434055 at 13. At 13 a dense /3- 

 shower occurred, the temperature rose to 17 -5 and the index fell to 1-430774 

 at this temperature, corresponding to a point on the /3-solubility curve. The 

 /3-crystals were stable for several hours, but the next day they had transformed 



to a. 



The details of all these experiments are plotted on fig. 6. Here again it will be 

 seen that at the points where the solutions attain their highest index the majority of 

 the index-temperature curves very approximately touch a curve parallel to the 

 solubility curve for the /3-modification. Of the fourteen curves representing the 

 above experiments which appear on fig. 6 only four, ranging in concentration from 

 9 5 '2 per cent, to 90 '6 per cent., do not behave in this way. In these experiments 

 the curves cross the supersolubility curve by from 2 to 4 '5 of temperature and 

 therefore pass appreciably into the labile region. These solutions may not have been 



