15$ 
Iron o 
The toughest iron and that which requires most fuel* is 
from the siliceous ores ; next to that the argillaceous ; the 
most fusible and least tough iron is generally from calca- 
reous iron-stones. All these I apprehend may be quali- 
fied by a due mixture with each other. 
[To, be concluded in next number /] 
The next number will finish the article Iron and also 
Steel. I wish I could have made the preceding papers 
more popular and less chemical, but I could not. The 
time is at hand when young iron masters will find it ne- 
cessary to become acquainted with chemistry ; to such, 
the present essay will furnish abundant matter for reflec- 
tion. It is not intended for the iron masters of the pre- 
sent day ; for men of great industry, great experience, 
and generally of great wealth honourably acquired. Such 
men need no instruction, and I am not competent to give 
it if they did. 
The other branches of manufacture, I shall treat in the 
Same way, more or less at length as my materials induce me, 
Wilkesbarrej March 1 6th, 1813. 
Bear Sir, 
HAVING observed by my last number of the Empo* 
rium of Arts and Sciences, that you had undertaken the editorship 
of that work, I send inclosed a copy of manuscript directions, in 
my possession, by an English manufacturer, for making bleach- 
ing liquor for the use of papermakers. I have preferred giving you 
an exact copy of it and the draught, to making any alterations in 
the style or drawing. Your knowledge of the subject will enable 
you to make the necessary corrections in both. 
As the method of bleaching, by means of the oxygenated muri- 
atic acid is, I believe, not known or in use in our paper-mills, it 
may be useful to the profession here to be informed, of the mod© 
and process of conducting in Europe that part of their business. 
I should be very happy to hear from you occasionally, and am, 
D ear Sir, 
Very respectfully your obedient servant, 
Professor Cooper, Carlisle, JASP. CIST 
