PREFACE. 
Two years and a half have elapsed, since the publication 
of the first volume of this Journal, and one year and ten 
months since the iiditor assumed the pecuniary responsibil- 
ity. Within this latter period, three volumes have been 
published, giving an average of a volume once in about sey- 
en months, and of anumber, once in half that time. It is in- 
tended, as far as practicable, to publish this Journal in quar- 
terly numbers, but on account principally of the great geo- 
graphical range from which the communications come, and of 
the large number of engravings, undeviating exactness on 
this point, is not always attainable. 
The work has not, even yet, reimbursed its expenses, (we 
-speak not of editorial or of business compensation,) we in- 
tend, that 2t has not paid for the paper, printing and engrav- 
wg ; the proprietors of the first volume being in advance, 
on those accounts, and the Editor on the same score, with 
respect to the aggregate expence of the three last volumes. 
This deficit is however no longer increasing, as the receipts, at 
present, just about cover the expense of the physical materials, 
and of the manual labour. Areiterated disclosure of this kind 
is not grateful, and would scarcely be manly, were it not 
that the public, who alone have the power to remove the 
difficulty, have a right to a frank exposition of the state of 
the case. As the patronage is, however, growing gradually 
more extensive, it is believed that the work will be eventu- 
ally sustained, although it may be long before it will com- 
mand any thing but gratuitous intellectual labour. 
It is regularly transmitted to Sicily, Italy, Switzerland, 
Germany, France, Sweden, Ireland, Scotland, and England, 
and occasionally to other foreign countries. In London, in 
consequence of an application to the Editor from that city, 
a regular arrangement has been made for circulating the 
Journal in Great Britain. Many of the periodical scientific 
works of Europe, and most of those of London and Paris 
are forwarded in exchange. 
Its domestic circulation is not local; it is transmitted to 
all the most important parts of the United States. 
Its most extensive patronage is derived from the city of 
Philadelphia, which takes more copies than any other com- 
munity ; the cities of New-York and Boston afford it about 
Lo] 
