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burners. The nearest plate was 12 inches above the flame, 
the other 3 inches above it. The burner was a large one, 
and lighted on the average 5 hours each day. The zinc 
plates were examined after three months, when it was found 
that the lower one had accumulated the usual brownish 
black deposit and also a furring of sulphate of zinc. The 
upper plate of zinc was little affected, which leads him to 
the belief that a single plate of perforated zinc of about a 
foot square is sufficient to remove the greatest part of the 
noxious emanations, and obviates to a great extent the ne- 
cessity of a globe or chimney. 
“ On the Relation of Electrical Resistance to the Chemical 
Composition of Steel Wire,” by William H. Johnson, B.Sc. 
I showed in a paper read before the Society in March last 
year, and entitled “ On the Electrical Resistance and its Rela- 
tion to the Tensile Strain and other Mechanical Properties 
of Iron and Steel Wire ” that in cast steel wires drawn in the 
same way but manufactured so as to contain different quan- 
tities of carbon, etc., the electrical resistance increased with 
the resistance to tensile strain, vide table B in the report of 
my paper. — Pro. Man. Lit. & Phil. Society, No. 12, vol. XIX. 
During the last year Dr. Burghardt has very carefully 
analysed the identical samples of annealed steel wire whose 
electrical resistance and other mechanical tests are given in 
table B just mentioned. The results for all samples with the 
exception of No. 6, not yet analysed, are shown in table C. 
A glance at this table shows us that five of the samples 
have only four elements other than iron present in quantity, 
namely, — carbon in two forms combined and graphite; sili- 
cone and manganese; and traces only of sulphur and phos- 
phorus. 
