124 SEVENTH REPORT—1837. 
picion that it is not a Swedish specimen; for as the Swedish 
ore is magnetic iron, and the fuel charcoal, the presence of 
sulphur in the iron is very unlikely*. 
In this specimen the atoms of iron and manganese are to 
those of carbon, silicon, and aluminum in the proportion of 42 
to 1, instead of 33 to 1, as in cast iron, No. 1. 
The atoms of carbon, silicon, and aluminum approach the 
proportions of 7, 2, and 1, so that in cast iron, No. 2, judging 
from one specimen, there is a greater proportion of carbon com- 
pared with the silicon and aluminum, than in cast iron, No. 1. 
Mr. Tennent analyzed a specimen of hot blast iron, No. 2, 
from Gartsherry. Its specific gravity was.6°9156, and its con- 
stituents, Atoms. 
Tron’-..* . . . ©. 90°542 > |. 25°86 hee 
Manganese . . . 2°764 0°78 
Carbon '... = 3:094 4°05 
Silicon . . . . 0°680 0°68 
Aluminum . . . 2°894 2°31 
Sulphur. . . . 0:023 0°011 
99°997 
So that it resembles cast iron, No. 1, in the proportion of its 
constituents.. The carbon is almost the same as in cold blast 
iron, No, 2, but the proportion of aluminum is four times as 
great, while the silicon is little more than half as much. The 
atomic ratios are, carbon 4°; silicon, 0°67 ; aluminum, 2°28. 
3. Five specimens of hot blast cast iron, No. 1, were analyzed. 
Two of these were from Carron, and three from the Clyde Iron 
Works, where the hot blast originally began, and where, of 
course, it has been longest in use. The specific gravity of these 
specimens was found to be as follows :-— 
Ist. From Clyde Works. . . . 7:0028 
9nd. From Carron. ... .  .« . »  g#O7aE 
Srd.. From‘ Carron’) '.099° 30.9550 $PO721 
4th. From Clyde Works. . . . 7°1022 
Mean . . 7:0623 
It appears from this that the hot blast increases the specific 
gravity of cast iron by about ;jnd part. It approaches nearer 
the specific gravity of cast iron, No..2, smelted by cold air, than 
to that of No. 1. 
The following table exhibits the constituents of these 4 speci- 
mens. 
* I have been told by Mr. Mushet that the Swedes add sulphur to their iron, 
No. 2. 
