124 
In papers which contain arsenic the hardness of the sur- 
face and the comparative firmness with which the colour is 
fixed on the paper are of course important factors in the 
danger which attends their use; a paper on which the 
colour is but loosely attached, though it may contain less 
arsenic, will be much more dangerous than one containing 
a much larger amount with the colour firmly adherent, the 
minimum of danger being reached in a “ glazed” paper, or a 
sized and varnished one. In any case, however, a sensible 
person will prefer not to live continually surrounded by so 
many square feet of arsenic-covered walls, and it is to be 
hoped that the promiscuous use of arsenical paperhangings 
will receive a permanent check on the completion of the 
labours of the Committee of the Society of Arts, which is, 
I understand, at present drafting an Act of Parliament to 
regulate the application of this poisonous substance, and 
endeavouring to decide upon a test to which suspected 
papers may be uniformly subjected. 
It is not a point to congratulate ourselves upon, that it 
appears to be the opinion that the Lancashire paperhanging 
manufacturers have the unenviable reputation of being 
greater offenders with respect to the presence of arsenic in 
papers than their fellows nearer the metropolis, and there 
can be no necessity, with the local scientific and techno- 
logical knowledge which is attainable, that this should be 
the case. 
It appears to be a moot point whether the cheaper or the 
more expensive papers usually contain more arsenic, and 
also in which class is it oftenest found. I hope to have an 
opportunity of making a communication to the Society on 
this point on a future occasion. 
Dr. Joule, F.RS., said that since Mr. Grimshaw read his 
paper on the sulphuric acid produced by gas lights, he had 
hung two finely perforated zinc plates over one of his 
