On the Freezing-points of Dilute Solutions. 197 



We had ourselves called attention to the fact that we had 

 at our disposal thermometers reading only to y^ ° direct, and 

 to yo 1 oo° by estimation, so that our determinations of the 

 lowering of the freezing-points could for this reason be accu- 

 rate to within only one to two thousandths of a degree. Mr. 



Jones's numbers, which read to 7p^°, are, as we have 



shown, untrustworthy to within at least hundredths of a degree. 



Mr, Jones then remarked that it was not " apparent " to him 

 why our two series for NaCl in very dilute solutions should 

 vary by 5 per cent. He neglected to remark that in reality 

 such differences are limited to the most dilute solutions, and 

 on that account lie within the limits of experimental errors 

 given by us. Moreover in the second series for NaCl the 

 greater values for the lowerings may be accounted for by the 

 presence of larger quantities of the solid substance, since in 

 this method larger quantities of undercooled liquid are intro- 

 duced. In any case it is self-evident to every one who knows 

 the elements of the computation of errors, that no conclusions 

 can be drawn presupposing a greater degree of accuracy in our 

 results than that given by us. Nevertheless in spite of this 

 Mr. Jones concluded, from our results with ethyl alcohol, that 

 a rise of the molecular lowering took place which was far 

 within the experimental errors. 



That we used substances of sufficient purity for the purpose 

 we had in view, that is, substances whose possible impurities 

 were absolutely unessential, we certainly did not especially 

 mention. Every one knows that comparatively pure NaCI, 

 ethyl alcohol, and cane-sugar are easy to obtain. 



We refrain from criticizing the few new experiments of 

 Mr. Jones, partly because we have not the least interest in 

 carrying-on a further controversy, partly because the criticism 

 given in our earlier research would simply need to be repeated 

 word for word*. Moreover Mr. Jones admits indeed the 

 influence of the external temperature (page 389), and in that 

 the existence of a great source of error which he formerly 

 entirely neglected. 



In conclusion a purely personal remark. Mr. Jones spoke 

 (page 385) of " the unusual lack of courtesy." That Mr. Jones 



* For instance, Mr. Jones maintained that the influence of his " gentle " 

 stirring was imperceptible, i. e. determined from his feeling instead of 

 quantitatively. That the thermometer-reading remained unchanged is 

 no proof for his assertion according to what our theory as well as experi- 

 ments showed. 



