i879-] 
British Association. 
687 
as dry air, at the moment of discharge the resistance along 
the line of discharge is practically nothing, and therefore all 
the charge is inducted away. Most of those tried failed. 
The survival of the fittest has been exemplified in the 
“ plate ” protector. In this form — one of the earliest intro- 
duced — one thick plate of brass is in connection with the 
earth, and another similar plate in connection with the line 
is placed above it, but separated from it by paper or by 
insulating washers. The lightning entering the wire, bursts 
across the paper or air-space in preference to passing 
through the apparatus, and thus escapes to earth. It is the 
practice of the Post-Office department to keep these plates 
apart by thin paraffined paper 0*002 inch thick. The paper 
contains an account of some important experiments by the 
author on plate-proteCtors, which confirm very decidedly 
the accuracy of the figures obtained by Drs. Warren de la 
Rue and Muller on the striking distance between two flat 
disks given by them in a paper read before the Royal 
Society. 
Section B. 
The Chemical Section (B) was presided over by Professor 
Dewar, F.R.S., who, in his opening Address, remarked that 
the time was past when the President could give a review 
of Chemical Work from year to year, so he took a broad 
view of the progress of Chemical Science. Referring to 
Messrs. Thomas and Gilchrist’s process for the elimination 
of phosphorus from pig-iron, Prof. Dewar said that by far 
the greater portion of iron ores contain very appreciable 
quantities of phosphorus. Of the total phosphorus which 
goes into a blast-furnace, whether with the ore or with the 
limestone, nine-tenths are contained in the resulting pig- 
iron. The Bessemer process did not eliminate phosphorus 
from pig-iron treated by it, and extremely small proportions 
of phosphorus render steel “ cold short,” so that the process 
had hitherto only been applicable to the rarer and costlier 
kind of pig-iron produced from exceptionally pure ore. Even 
thus restricted the Bessemer process had produced results 
of incalculable importance, and the imagination could scarcely 
grasp the extent of the further development it must receive 
and the importance of the further benefits which must now 
flow from it. 
We have not sufficient space to refer to the many valuable 
papers brought before this Section. We must, however, 
mention a note by Mr. J. Norman Lockyer, “On the Sup- 
3x2 
