_New-York, 14th November, 1843._
THE Gardeners' Chronicle, published in England, has the following
criticism on my essay of dock-mud, inserted in your April number of
this year, page 13:--
"We trust the editor is more correct in his other statements than in
this, concerning the percentage of sea-salt in guano, which contains
little more than a trace of it."
I have never analysed the guano, but depended on one or two analyses
given by Professor Johnston, reader of chemistry in the University
of Durham, England, in the appendix to his Lectures on Agricultural
Chemistry. He gives tables of contents of two parcels, the first
containing 30.3 per cent., the second rather more than 11 per cent.
of sea-salt. I took the larger quantity, to prove that if dock-mud
contained sea-salt, it could be no objection to it as a fertilizer.
It is highly important that the tables of analysis of celebrated
manures should be correctly given, and if the editor of the Chronicle
can furnish correct tables, he will be conferring an important boon on
the agricultural community of the whole world.