482 



SCIENCE 



[N. S. Vol. XXXII. No. 823 



ten to one hundred times its weight of water are 

 shaken and allowed to stand in tall jars or cyl- 

 inders, there develops almost at once a sharp sur- 

 face between the falling kaolin and the clear solu- 

 tion above. This surface sinks as the kaolin con- 

 solidates and its rate of fall represents the rate 

 of consolidation of the kaolin. The curve repre- 

 senting the relation between the position of this 

 surface (or the apparent volume of the kaolin) 

 and the time of standing has been found to be an 

 hyperbola, the central portion of which may be 

 represented quite well by an exponential equation 

 analogous in form to that of the mass law. On 

 both ends of the curve the fall is slower than 

 required by this equation. The reasons for these 

 retardations are being more fully investigated. 



The Action of Potassium Hydroxide upon Kaolin 

 Suspensions: F. K. Cameron and E. E. Fbbe. 

 The authors have studied the action of varied 

 concentrations of potassium hydroxide on the de- 

 gree of floeeulation { and hence of the rate of 

 settling) of suspensions of one gram of finely 

 powdered kaolin in 100 c.c. of water. In very 

 dilute solutions there is no noticeable action. At 

 a concentration of about 0.015 gram KOH per liter 

 of solution there begins suddenly a strong defloc- 

 culation or decrease in the degree of floeeulation. 

 At about 1 gram per liter the degree of floeeula- 

 tion begins to increase slowly and at about 4.5 

 grams per liter the degree of floeeulation is the 

 same as in pure water. This increase continues 

 with increase in the KOH content and at about 

 10 grams per liter the degree of floeeulation 

 reaches a maximum after which it very slowly 

 decreases. This final decrease is probably more 

 apparent than real and due to the direct effect of 

 the increased viscosity and density of the solution 

 on the rate of settling. 



Heats of Reaction in W on-aqueous Solvents (pre- 

 liminary paper) : J. Howabd Mathews. 

 The first reaction chosen for study was the 

 exact neutralization of 1 molecule of pyridine by 

 1 molecule of acetic acid. The product of this 

 reaction is a liquid, and remains in solution in 

 all of the solvents used. The heat evolved by this 

 reaction in ten different solvents was measured by 

 a slight modification of the adiabatie method 

 devised by Richards and Rowe" for measuring 

 specific heats of liquids. The quantity of heat 

 evolved was found to depend on the solvent used. 

 In solvents where side reactions were impossible 

 the values obtained were of the same order as the 



-Z. physik. Chem., 64, 187, 1908. 



value obtained where no solvent was used, but the 

 differences were much greater than the experi- 

 mental error, which was certainly less than 0.1 

 per cent. The study is to be continued. 



A Suggestion to Instructors in Quantitative An- 

 alysis: W. C. Ebatjgh. 



Material for use of students in quantitative 

 analysis can frequently be obtained from com- 

 mercial laboratories in the neighborhood of a 

 technical school, and will save much time and 

 trouble as well as expense to teachers. The por- 

 tions of samples that have been analyzed, or 

 reserve samples that have been prepared for the 

 use of an umpire, but not needed for that purpose, 

 are issued to students, and as the analysis results 

 used for settlement are furnished by the labora- 

 tories that prepared the samples the work of the 

 students can be checked accurately. It has been 

 found that students take a greater interest in 

 analyzing such samples than in working with 

 material that has not been in commercial use. 

 A Reported Occurrence of Native Iron: W. C. 

 Ebaugh. 



A sample of metal, thought to be platinum, was 

 sent to the University of Utah by Cecelia M. 

 Gettings, of Moab, Utah. Later a second sample 

 from the same source was received, and an affi- 

 davit accompanied it declaring that the material 

 had been found in a certain mining (placer) 

 claim in the La Sal Mountains east of Moab. The 

 material proved to be magnetic, was malleable, 

 had a specific gravity of 7.82, and upon analysis 

 yielded 



Carbon 0.08 per cent. 



Silicon 0.20 per cent. 



Phosphorus 0.0003 per cent. 



Sulphur undetermined 



Manganese traces 



Nickel absent 



Cobalt absent 



Aluminujn absent 



Chromium absent 



There seemed to be no question in the minds 

 of the men who discovered the metal that it was 

 of native occurrence, and could not have come 

 into the deposit from tools or other articles made 

 by man. 

 Equilibrium in the System KI, I and Aqueous 



Alcohol: C. L. Pabsons and H. P. CoEMSS. 



Equilibrium experiments carried out in detail 

 show positively that no solid polyiodides of potas- 

 sium exist at 25°. The solubility curves were 



