Some Physical Properties of Nitric Acid Solutions. 113 



It will be evident that in this experiment, purposely conducted in 

 AH exaggerated form, the difference produced is very small, and 

 therefore it may safely he concluded that no appreciable effect 

 would be caused by a very thin film of paraffin in experiments 

 M'hich lasted for 3 hours on an average. 



III. Glass of Tliermometer introduced into the Acid. For the greater 

 period of time during which the experiments were conducted the 

 thermometer hole was closed with a quartz plate; as the thermo- 

 meter, made of lead glass, was introduced for only a short time it 

 may reasonably be assumed that the quantity of glass dissolved out 

 under these conditions would be insignificant. 



IV. Personal and Experimental Error due to Micrometer Screw. The 

 majority of adjustments were probably accurate to 2" or a possible 

 extreme error of 4", a magnitude which would change the value of 

 \i for the weakest acid by 0-000019 and for the strongest of 



0-000008 ; the values for \L are therefore correct in most cases to 

 one unit in the fifth place with a variation in the sixth place. 



XL Temperature Coefficient*. 



In order to determine the above values, the sample alluded to above 

 raay be given as an illustration and the following results cited : 



Temperature k-orr.). Value of fj. D . 



11 -G 1-407157 



18 -.1 1-409349 



Differences... 0-002808 



from which a decrease in \j. of 0-000432 is obtained for increase of 

 1 temperature; two other determinations gave ^ D 15 ' 3 = 1*405558 

 and /x D 13 = 1-405567. Accepting this temperature coefficient there 

 are thus four values for the reduction of f* D to the standard tempera- 

 ture taken, 14*2, and the degree of concordance is shown below : 



Temperature. MD reduced to 14'2. 

 11-6 1-406034 



13-0 -406049 



15-3 -406033 



18-1 -406034 



Mean ... 1-406037 



In like manner the temperature coefficients expressed in terms of /*;> 

 were determined for all the other samples of acids and the values reduced 

 to the standard temperature as shown above. The following table 

 gives these coefficients : 



