1898.] on Some Becent Results of Physico-Gliemical Inquiry. 649 



Ethers. 



Ethyl ether CH3.CH2.O.CH..CH3. 



Methyl propyl ether CHj.O.CHj.CH^.CHs. 



Ethyl propyl ether CH3.CH2.O.CH2.CH2.CH3. 



Dipropyl ether CH3.CH..CH..O.CH,.CH2.0H3. 



Methyl isobutyl ether CH3.0.CH2-CH(CH3)2. 



Ethyl isobutyl ether CH3.CH2.O.CH2.CH(0H3)2. 



In speaking of the results of the observations on these substances 

 the lecturer drew special attention to the case of water, more parti- 

 cularly as regards the efifect of temperature in altering its viscosity. 

 The lollowing table shows the viscosity of water in absolute measures 

 at temperatures between 0° and 100° C. 



The results of these observations are graphically represented in 

 Fig. 3, in which viscosity coefficients are ordinates and temperatures 

 are abscisssB. 



A special series of observations was made in order to ascertain 

 if, as inferred by Moritz, water had a maximum viscosity in the 

 neighbourhood of 4°, but no indication was given of any anomalous 

 change in the rate of variation between 0° to 8°, and the lecturer 

 pointed out the bearing of this fact upon the supposition that water 

 at low temperature is a solution of ice, richer and richer in ice as it 

 is more and more cooled. 



The so-called anomaly of water possessing a point of maximum 

 density remote from its point of congelation, must be connected with 

 its other physical properties, and observation shows this to be the 

 case. Water, like all other liquids, is compressible, but whereas in 

 the case of all other liquids the compressibility increases with the 

 temperature, it is found that water at low temperature is more com- 

 pressible than at high temperatures. It has also been shown that 

 water is " anomalous " in respect to its behaviour when heated under 

 pressure. The degree to which it expands for a given interval of 

 temperature steadily increases with the pressure, and especially at 

 low temperatures, contrary to what is usually observed. The viscosity 

 of water is also affected by pressure. It has been shown by Warburg 

 and Sachs, and also by Rontgen, that water at ordinary temperatures 



