STANDARD THERMOMETER. 



A standard thermometer of the following description was also adopted : 



The thermometer shall be graduated in one-tenth degrees from 10 to 60 C, 

 with a zero mark, and have an auxiliary reservoir at the upper end, also one 

 between the zero mark and the 10 mark. The cavity in the capillary tube be- 

 tween the zero mark and the 10 mark must be at least 1 cm below the 10 mark. 

 The 10 mark is to be about 3 or 4 cm above the bulb, the length of the ther- 

 mometer being about 15 inches over all. The bulb shall be of Jena normal 16 U1 

 glass and the thermometer annealed for seventy-five hours at 450 C. The bulb 

 shall be of moderately thin glass (so that the thermometer will be quick acting) 

 and be about 3 cm long and 6 mm in diameter. The stem of the thermometer 

 shall be 6 mm in diameter and made of the best thermometer tubing, with scale 

 etched on the stem, the graduation clear-cut and distinct, but quite fine. The 

 thermometer shall be furnished with a felt-lined case. 



It was recommended, however, that further study be made of the 

 method to be employed in drying the fatty acids. 



II. DIFFERENTIATION OF THE " COLD TEST" AND THE "CLOUD TEST." 



As a result of correspondence with chemists interested, a collection 

 of the various methods used in this country in making the cold test has 

 been made. A study of these methods shows that there seem to be two 

 well-defined tests commonly classified under the title of "cold test." 

 One is the temperature at which an oil becomes turbid because of the 

 crystallization of some of the constituents of the oil, and the other is the 

 temperature at which an oil will flow. In consideration of the fact that 

 the cloud test very well describes the clouding due to the separation of 

 the crystals, it would seem to be better to limit the meaning of " cold 

 test" to that class of tests where the temperature at which the oil will 

 flow is determined, and "cloud test" to the class of tests in which the 

 temperature of clouding is obtained. This will enable us to convey a 

 definite idea when we speak of " cold test" and "cloud test." 



There seems to be no doubt that these two tests represent different 

 determinations. The cloud test gives the temperature at which the 

 more solid fats or oils begin to crystallize, and when we consider that 

 all oils are made up of substances varying widely in their crystallizing 

 points, it would seem hardly possible that the information given by this 

 test could have the same meaning as a determination of the congealing 

 point of the whole oil, which is the information given by the cold test. 

 Moreover, there are two classes of oils to consider first, the edible oil, 

 which must remain clear at a certain temperature, and, second, the 

 lubricating oil, which must flow at a certain temperature. A test like 

 the "cloud test" is the one to be applied to the edible oils, while the 

 " cold test," which gives information regarding the temperature at which 

 the oil will flow, will be the only satisfactory test to apply to lubricating 

 oils. 



