28 Kansas Academy of Sciexce. 



arms, the shorter arm of which is sealed, a small quantity of water is placed. A column 

 of mercury is introduced next, to separate the water from the outer air, this column be- 

 ing of such length as to bring the water under a total pressure of a few millimeters less 

 than one atmosphere. If the tube thus filled be placed in a bath of boiling water, the 

 water within the tube will boil, and the mercury will be driven outward until it stands 

 at the same height in both arms of the tube, or until the vapor formed has reached its 

 maximum tension. At the same time a small bubble of air will be excluded from the 

 boiling water, which upon cooling can be removed from the tube. If this process of 

 boiling, cooling, and expelling the excluded bubble of air, be repeated until on further 

 boiling no bubble is formed, the water will finally refuse to boil when the tube is placed 

 in the water bath ; and in the oil or paraffine bath it can be heated to 130°, as in Donny's 

 experiment, without ebullition. At this temperature vapor is suddenly formed, and the 

 mercury is violently expelled from the tube* The apparatus then only needs refilling 

 to be ready for a repetition of the experiment. 



The writer hopes, with the aid of this very simple apparatus, to make a more de- 

 tailed study of the superheating of various liquids, and of the attendant phenomena, 

 than has been possible hitherto. 



THE UTILIZATION OF MINERAL WATERS. 



BY E. H. S. BAILEY. 



There has been for the past few years a growing interest in the subject of the purity 

 of water supply. Whether for municipal supply, for boiler purposes, for use in manu- 

 factories, or for domestic use, people begin to realize that certain constituents are danger- 

 ous, others of no use, and others detrimental. It is difficult to draw the line sharply 

 between potable waters and so-called mineral waters. If we attempt to put a maximum 

 limit to the solid residue that a potable water shall contain, there are numerous mineral 

 Maters, acknowledged to be of value, that do not contain a tenth the amount. Again, 

 very hard waters are often richer in mineral constituents than the so-called mineral 

 waters. A mineral water, then, may be defined as one containing an abnormal amount 

 of solids, or containing some unusual constituents. Chalybeate, Borax and Lithia springs 

 belong to the latter class. It often occurs that waters, like those of many of the Saratoga 

 sju-ings, contain 800 to 1,000 grains of solid matter per gallon, and also comparatively 

 rare elements, such as Bromine, Iodine, and Lithia. 



Water, the great solvent, has taken into solution — has selected, so to speak, from the 

 variety of material through which it has flowed — certain substances. Though we may 

 make artificial mixtures closely resembling the natural, it is found difficult to exactly 

 imitate nature. An interesting case was up for consideration a year or two ago in the 

 Tinted States Department of Customs. It seems that natural waters are admitted free 

 of duty, while artificial waters are taxed. The Apollinaris Company were anxious to 

 import duty-free; but it was shown by chemical experts that the spring water was salted 

 and surcharged with carbonic acid gas before being bottled, and so became an artificial 

 water. The Secretary of the Treasury, however, overruled the opinion of these experts, 

 and of the Attorney General, and all duties were remitted, much to the disgust of those 

 engaged in bottling American spring waters. 



*Tht' apparatus here described is given in some text-books on physics (see Dechanel's Natural Phi- 

 losophy, part 1 1 1, its object being to illustrate the tension of vapor formed when a liquid boils under 

 atmospheric pressure. The behavior of the liquid when all air is expelled, as above described, seems 

 not to ha\ e Inch observed. 



