ELECTROMOTIVE FORCES IN THE VOLTAIC CELL. 481 



gradually returned to nearly their former state. He tried if he could 

 remove the gas film from one of the plates by exhaustion under an air- 

 pump, and the plate so treated exhibited a difference when taken out and 

 compared with an ordinary plate ; but he was cautious enough to repeat 

 the experiment, leaving the plate under the bell jar for the same time and 

 not exhausting. The same difference appeared, so he attributes it to 

 possible grease. 



This is the right sort of way to make experiments, and if everybody 

 experimented with proper care there would be vastly fewer papers pub- 

 lished in Germany, and science would progress on the whole faster. 



At present it feels to me overladen with a mass of publication, mostly 

 of necessity by men of not absolutely the first order, much of it with no 

 sort of clearness or insight, but rough, crude, and ill-digested. A man 

 makes a number of experiments ; he does not stop to critically examine 

 ;md weigh them, and deduce from them their meaning, nor indeed does he 

 often take the trouble to examine whether any definite meaning can in 

 their then shape be drawn from them ; but he rushes with them into 

 print, producing a memoir of wearisome length and sometimes extreme 

 illiterateness of style. 



Some one else then has the trouble of wading through the heap to see 

 whether any fragments of value may perchance be imbedded in it, and 

 probably he is unable to come to much definite conclusion, because he 

 cannot be in so good a position for criticism of the experiments as the 

 original author was. He therefore writes a paper pointing out defects 

 and errors in the communication. Others take up the same line, the 

 original man replies, and so there is a controversy, and nothing is really 

 settled at all. Finally, some one else independently goes over the whole 

 ground from some distinct point of view, makes a few well-planned, clear, 

 and decisive experiments, describes them in a compact and readable form, 

 and there results a definite gain to science. But how much better would 

 it have been if this last paper had been the only one published ! Unless a 

 man is an experimental genius of the highest order, it is necessary for him 

 to think for far more time than he experiments, if he wishes to advance, 

 and not to lumber, his science. If it be objected, as indeed it may with 

 great truth be, that one man's life and capacity are not sufficient for this 

 in the present state of knowledge, the objection constitutes a strong argu- 

 ment in favour of the proposition that the time has come for an organi- 

 sation of science and a more definite division of labour. 



To return to the experiments of Herr SchultzeBerge. One is not 

 able to say after all that they are very satisfactory, for they do not 

 distinctly settle any question. The general conclusion he draws from 

 them is the apparently safe one that the contact force between a metal 

 and a gas is not in general the same as between a metal and air. Even 

 this is not absolutely safe, however, because it might conceivably be that 

 an air /gas contact force caused all the difference. Granting that this is 

 unlikely, the experiments are in favour of a contact force between metals 

 and air or gas, but they do not establish the fact any more strongly 

 than, if so strongly as, Mr. Brown's experiments had already done : the 

 weak point in both is the possible corrosion of the plates and formation 

 of films of alloys or compounds, which may be the real source of the 

 observed difference of potential. 



And against the existence of a contact force between metals and various 

 gases, the experiments of Pellat and others are to be remembered, which re- 



1884. i i 



