276 VALUATION OF BLEACHING POWDER. 
the editorial discussion of the subject, in the August and 
September numbers of the Pharmaceutical Journal. 
It has recently been stated in our daily papers that the 
frigate Raritan, which had been abandoned at anchorage in 
the Chesapeake Bay, owing to the contagious miasm that 
infected her hulk since returning from the tropics, was en- 
tirely disinfected by the application of some disinfecting 
agent, the name of which was not mentioned. May it not 
be one of the salts in question, most probably the nitrate of 
lead? W. P. Jr. 
ART. LXXIII. — ON A CHLOROMETRIC PROCESS FOR THE 
VALUATION OF BLEACHING POWDER. 
By F. Grace Calvert, Esq. 
(Read before the Philosophical Society of Manchester.) 
The process to which I beg to call your attention is not 
entirely new, being Gay Lussac's method by arsenious 
acid, which I have transformed from the French system 
into the English, and, I hope, made it sufficiently simple to 
be employed by bleachers, or other persons not accustomed 
to much chemical manipulation. 
It was the knowledge, proficiency, and precision required 
under Gay Lussac's method, which prevented the great 
majority of bleachers, even in France, from adopting it. 
Let us throw a glance at the different methods which 
have been employed to test bleaching liquors. The first 
one was called Bertholimetre, from the celebrated Chemist, 
who was the discoverer of it, although it was first published 
in 1794 by a person of the name of Decroizilles. It was 
based on the power possessed by chlorine to destroy the 
colour of indigo. His standard liquors were made with one 
