ON THE ELECTRICAL PROPERTIES OE PURE SULPHUR, 
59 
similar diminution of resistance, and in this case Quincke’s explanation is impossible. 
The suggestion is obvious that the phenomena observed by Quincke may possibly be 
real phenomena—not depending on dust particles—and if this be the case, then it is 
clear that a valuable discovery has been rendered unavailable by the source of 
uncertainty we are dealing with. 
In the following statement we shall explain with some minuteness the methods 
adopted for purifying our material, and give a summary of the conclusions to which 
previous observers have been led as to its physical properties. We shall then explain 
in a general way the methods we have used for determining the electrical properties. 
This will be followed by a short treatise on the construction of sensitive galvanometers 
of high resistance, together with an account of the experiments which have led us to 
the construction of our instrument, of which full details and drawings will be 
furnished. We shall then proceed to deal with our various experiments. At the 
present time the experimental work is still in full progress, and is likely to continue, 
for in investigating properties of substances the end is only reached when the observer’s 
interest falls off. Our chief reason for publishing is that we consider the main 
features are now pretty well established. 
Section I. 
On the Preparation and Properties of Pure Sulphur. 
§ 1. General Discussion of Causes, Procedure, &c. —Our information on the trans¬ 
formations of sulphur is chiefly derived from the following authors :— 
185G. C. Sainte-Claire Deville, ‘ Ann. de Chim. et de Phys.,’ Ser. S, vol. 47, 
p. 94. 
1854. Magnus, ‘ Pogg. Ann.,’ 1854, vol. 91, p. 308. 
1854. B.-C. Brodie, ‘ Proc. Boy. Soc.,’ vol. 7, p. 24 (March 30th, 1854). 
1856. Mitscherlich, ‘ Jour, fur prakt. Chem.,’ vol. 67, p. 369. 
1857. Berthelot, ‘ Ann. de Chim. et de Phys.’ (3), vol. 49 (two papers). 
0. Petersen, ‘ Zeitschr. fur Phys. Chem.,’ vol. 8, p. 608. 
1884. Beicher, ‘Chem. Centr. Blatt,’ 1884, p. 450. 
1889. J. Monckman, ‘Proc. Boy. Soc.’ for 1889, vol. 46, p. 136. 
1874. D. Gernez, ‘ C.B.,’ vols. 79, p. 219, 82, p. 1151, 83, p. 217. 
There are a large number of other observers whose work does not bear so precisely 
on the subject of the present investigation, and whose names are recorded in the 
“ Sachregister zu den Annalen der Physik und Chemie,” published in 1888, p. 563. 
Amongst the authors mentioned, we have found the papers of Brodie and 
Berthelot of most service. Brodie gives an account of the transformations of 
sulphur, but unfortunately omits many details, particularly as to the mode of 
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