Chemistry and Physics. 331 



carried out successfully, at least at certain localities, and will 

 allow the production of sulphur at a cost of about $12 per ton. — 

 Jour. liidust. and Eng. Chem., ix, 872. h. l. w. 



2. 2^he Use of Large Glass- Stoppered Containers in Autoclav- 

 ing. — Robert B. Krauss has devised a convenient method for 

 heating rather large quantities of liquids or solids under pressure 

 in order to avoid the expense and other difficulties connected 

 with the use of sealed glass tubes and of glass enameled auto- 

 claves. The material to be heated is placed in a glass bottle with 

 a ground stopper, the clean, dry stopper is twisted tightly into 

 the neck of the bottle and fastened securely with a clamp of suit- 

 able design. The bottle is then placed in an autoclave which is 

 half-filled with water and the apparatus is then closed and heated 

 to the desired temperature. Bottles used in this way have stood 

 pressures of 5,000 lbs. per square inch when heated in a specially 

 designed autoclave. It is obvious that under proper conditions 

 the internal and external pressures on the bottle are practically 

 equal. The autoclave used was drop-forged from armor-plate 

 steel and then machined. Its walls were two inches thick, and it 

 would take in a bottle of 5 liters capacity. It had a maximum 

 working pressure of 10,000 lbs. per square inch, was provided 

 with a suitable safety-valve, and was heated by a gas burner in a 

 special room provided with very thick, concrete walls. — Jour. 

 Amer. Chem. Soc, xxxix, 1512. h. l. w. 



3. A CryoscopiG Method for the Determination of Added 

 Water in Milk. — J. T. Keister calls attention to the fact that 



the numerous determinations of the freezing-point of milk found 

 in the literature show a remarkable uniformity. In general, this 

 temperature is from —0*54 to — 0*5'7°C. Hence the value of 

 this determination for detecting added water in milk is evident. 

 No determination of any constituent of milk has given such 

 closely agreeing values as this. It is evident that fat, the most 

 widely varying constituent of milk, has no influence on its freez- 

 ing-point, while such substances as albuminoids which are present, 

 perhaps, in a colloidal condition, or, in any case, have a very high 

 molecular weight, must have a very small effect upon it. The 

 only constituents, therefore, that exert any appreciable effect 

 upon the freezing-point are the soluble lactose and the salts, 

 which consist largely of the chlorides of the alkali metals. It 

 appears further that there is a more or less constant relation 

 between the lactose and the sodium chloride present, and that 

 when one increases the other diminishes, so that there is a ten- 

 dency for these substances to balance each other in their effect 

 upon the freezing-point. 



By the use of a Beckmann thermometer graduated to 0-01° C 

 the author has examined a large number of samples of milk for 

 their freezing-points, and has found that the results are remark- 

 ably uniform, and that the addition of as little as 5 per cent of 

 water can be detected with certainty by this method. It is 

 essential, however, that the test be applied to reasonably fresh 



