110 Dr.8. B.Schryver. Some Investigations Dealing [ Aug. 12, 
easily recognised owing to the etched mark. When the liquid has come to 
rest, the height of the liquid in the capillary tube is read. The levels can be 
altered by squeezing the indiarubber ball, or by letting liquid out by tap B. 
The liquid should be passed through the apparatus and up the capillary tube 
several times until a constant reading is obtained. This is especially 
important in the case of liquids of high surface tension, which do not readily 
wet the glass. After using, the apparatus is washed out with water, and then 
with the fresh liquid of which the physical constant is to be measured. The 
little cup at the top of the capillary tube is for the purpose of collecting the 
wash-water and preventing it from soiling the outside. 
Between every two or three determinations, a control measurement with 
pure water was interpolated, so as to ensure that there was no derangement 
of the zero point, and no error due to alteration of temperature. 
All the solutions employed were made up with water which had been 
distilled in glass vessels over permanganate, and the apparatus and all the 
vessels employed had been previously soaked in concentrated sulphuric 
acid, and subsequently washed with the special distilled water before use. 
The readings were made with a magnifying glass. 
The surface tension determinations given in the accompanying table 
were the mean of several closely concordant readings (in most cases to 
within 0-1 mm.), many of them made after long intervals of time. 
As unity was taken water, to 100 c.c. of which one drop of 0°5-per-cent. 
phenolphthalein in 50 per cent. alcohol had been added.* This addition 
made only a very minute difference in the reading. The specific gravities of 
the solutions were determined gravimetrically in the ordinary way. 
Table I.—Surface Tensions of Normal Salt Solutions (Room Temperature). 
Inorganic salts. Organic salts. 
| Sodium chloride ¢....:...-....06-. 1 032 Sodium tormate. :.2.) seer 1 -020 
pe ADTOMNGEC erste tn ee oe 1 ‘024 pe lactate o..... tue onaeeeaeee 1°013 
| BL Snibratess) seems tee 1 023 a) acctate. 11 Seen ee 1 -004. 
he BNOGTUe ye eeese rer torr at 6 1-005 »  monochloracetate ...... 1 002 
| sulphocyanide:’:......™ 1 000 »  dichloracetate............ 0-970 
»  trichloracetate ......... 0 ‘905 
Eathiim “ehloride@ieernc: ses ot 1 -029 we salicylate. 4/10. cee eranas 0 902 
Potassium <1) 5 Perec eae ek 1 ‘028 Pamubenzoate .. vcs aun ne 0 ‘897 
Majenesinim (7,0 eeace ea ee 1 080 EMIMALONALC.....q..eeumeeee 1 0185 
Calcium WO MINED anlee's scant 1 ‘028 Wer msuceinate... 7.5. cage te 1-016 
Sie volehGeDavyeme ys) .68a5nnoduenoddns: 1 ‘029 S MPEDATORAGC. © |... acs ue ener 1 Oo 
| Barium Pie OS SoReal FOS 4e Pe ME ACUUVATO ) 14. 00k sana eee | 1 ‘0105 
* See p. 108 for method of preparing standard solutions. 
