I N D U S T R I A L A N D ENGI NEERING CHEMISTRY
40
Vol. 16, No. 1
however, the suggestion appears warranted that alteration in colloidal state may possibly constitute a factor of influence upon the molecular tautomerism. In a very few instances in the present investigation the symmetrical type of modification of absorption curves without displacement, to which reference has been made, has been observed to accompany dilution. If this phenomenon may be accepted as indicative of solvation, as seems possible, it appears to be necessary to conclude that but little evidence has been obtained of the occurrence of extensive solvation in aqueous solutions of dyes in general.
Apparatus for Providing a Continuous Stream of Hot Distilled Water' By Chester L. Ford STRUCTURAL MATERIAWRESEARCH LABORATORY, CHICAGO, ILL.
WAVE LENGTH FIG. VI-NEW METHYLENE BLUEN 1 1000 parts per million 2 = 40 parts per million 3 1 part per million
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gradual and progressive displacement and the phenomenon would not assume the character of a transition between two widely separated bands with an entire absence of development of intermediate bands. It is evident, furthermore, that if the absorption bands which are characteristic of concentrated solutions are to be accepted as evidence of decided alterations in colloidal state, the characteristic spectroscopic behavior of the dyes which have been examined should be susceptible of correlation with their colloidal behavior. I n point of fact, no correlation appears possible between the observed phenomena and the accepted colloidal rating of dyes. I n view of these considerations the writer would reject any hypothesis of a fundamental relation between the extreme
WAVE LENGTH FIG.VII-NILE BLUE2 B 1 = 825 parts per million 2 20 parts per million 3 1 part per million
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modifications in absorption observed and colloidal phenomena, even if the opposed hypothesis of an assumption of molecular tautomerism did not appear t o be both necessary and justified. I n further consideration of the evidence which has been accepted as indicative of appreciable alterations in colloidal state with many dyes under the experimental conditions,
T H E R E has been a long-felt want for a steady stream of hot water for washing precipitates without the necessity of blowing into or otherwise stimulating a wash bottle. To meet this need the writer took one of the ordinary variety and modified and added to it as shown in the accompanying illustration. The usual short length of rubber connection a t the nozzle was replaced by a wash h e consisting Disfilled of about 6 feet of gum tubing, a Wafer pinch clamp, and a rounded nozzle. To provide a reserve supply of water, an ordinary acid bottIe, B, is inverted over the flask and connected to it by the tube C , which extends from the bottom of B to about halfway to the bottom of the boiling flask A . To fill the apparatus, the tube D, which serves as a steam-escape vent when the water is boiling, is connected to the distilled water supply line G. If distilled water is supplied under sufficient pressure, opening clamp E allows the system to fill to a little below the level of the air tube F. If there is not sufficient pressure, suction is applied below E. The tube F reaches to the upper end of the bottle, but the water level is brought only to within an inch of this point. After filling, clamp E is closed, so that the water will FIG. 1 flow into flask A only as the water level falls below the level of connecting tube C. The various units were all attached to a 0.5-inch steel rod, 40 inches long, mounted on a shelf 16 inches above the top of the table. This has been found to give sufficient pressure for all ordinary washing. By regulating the amount of heat applied, it is possible to keep the water in the flask at, or close to, the boiling point, even when a considerable stream of water is being drawn off. One of the outfits now in use in this laboratory gives very satisfactory results with two wash lines instead of one. After the rubber once becomes heated there is very little loss of heat and the wash water delivered from the nozzle is close to the boiling point. 1
Received November 26, 1923.
