70 | Scientific Intelligence. 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PHysIcs. 
1. Correction to the paper on Argon, Prout’s Hypothesis and 
the Periodic Law; by Epwin A. Hitt. (Communicated.)— 
The author of the above paper, published in the May number, 
desires to call attention to an unintentional omission for which he 
is responsible. On page 408, reference is made to “ Lord Ray- 
leigh’s paper” and on p. 416 it is stated that “ Lord Rayleigh has 
shown that at 13° C. water absorbs 4 per cent of its volume of 
argon, etc.” In both cases no reference is made to the name of 
Professor Ramsay, who shared with Lord Rayleigh the joint 
authorship of the important papers referred to as well as the 
experimental work upon which they are based. This omission 
was unintentional and was indeed noticed before the paper was 
actually printed although too late to correct the proof. The 
scientific world appreciates so well the very important work of 
Professor Ramsay as co-laborer with Lord Rayleigh in this mem- 
orable research that this correction may seem to some unneces- 
sary, but the author feels that it is due to himself that he should 
not fail to make it. 
Two other corrections should also be made in the same article : 
In the note to page 414, 2d paragraph, for “ sélent discharge” 
read “electric spark” and on page 408, line 15, for “‘ force of 
gravitation” read “ forces of attraction.” 
2. Porosity of solid bodies for the Light Hther.—ZEuNDER 
describes an interference apparatus by means of which he has 
endeavored to detect movements.of the ether in connection with 
movements of surrounding bodies. The work was undertaken 
to test the following hypotheses of Fizeau, that either the ether 
adheres to the molecules of bodies and shares their movements ; 
or that it is free and is not influenced by such movements; or 
that only a portion of the ether is free and that another portion 
is bound to the molecules of bodies and moves with them. 
Zehnder’s apparatus consisted of an air-tight receptacle connected 
with long tubes through which light can be sent and suitably 
refracted and reflected in order to produce interference bands. 
By means of a moving piston the air in the tube can be set in 
motion and a change in the interference bands can be noted. 
Afterward the entire apparatus is exhausted of air and again the 
piston is moved in order to set the ether in movement. No 
change however could be observed in the latter case, and Zehnder 
remarks upon the limits of porosity of iron for the light ether. 
Michelson’s experiments on the relative motion of the ether and 
the earth’s atmosphere are commented upon and are repeated 
with similar negative results. The author concludes that the 
relative motion between the earth and the enveloping ether, at 
the observing station in Freiberg, did not attain the value of the 
