THE WOODS OF COMMERCE. 
The engraving represents an improvement on the original plan ; for the opportunity of presenting 
it we are indebted to Mr. Waring ton, who has also kindly furnished the following additional observa¬ 
tions founded on his now more lengthened experience:— 
“ Since the reading of my paper before the Chemical Society, on March 4, 1850, respecting the 
Miniature Aquarium ( Quarterly Journal of the Chemical Society , iii. 52), I have continued the investi¬ 
gations, introducing other water plants, and also three other varieties of water snail. But the principal 
alteration has been the construction of a better form of vessel for holding the water, as I found that 
the globular form of the glass receiver, produced a distortion in the vision of the fish, besides being 
very inconvenient for observation. I have therefore adopted the form of vessel, of which a sketch is 
appended, having flat surfaces of plate-glass at the hack and front, the bottom and ends being formed 
of slate, and supplied with a loose plate of glass at the top to keep out dust and soot. To render the 
whole more ornamental, as it was to stand in a sitting room, some pieces of tufa, or sandstone, were 
attached to the ends by means of Roman cement, so as to form ledges and slopes rising from the water 
line, on which mosses and ferns, such as luxuriate in an atmosphere loaded with moisture, could be 
grown. These materials are set in a stout angular zinc framework, and connected with a mixture of 
white-lead ground in oil, to which about an equal quantity of red-lead is added. This arrangement I 
have found to answer all my expectations, as it has been going on most flourishingly since January 1851. 
The plants consist chiefly of Hymenophyllum tunbridgense, and H. Wilsoni, Trichomanes speciosum, 
Blechnum boreale, Adiantum Capillus- Veneris , and several mosses. The whole of the interior can be 
viewed with the greatest ease, so that the natural habits of its living inhabitants can be watched and 
accurately noted in every particular. 
“ The rapid increase in the growth of the Vallisneria is very extraordinary. As I have before 
mentioned, the plants of necessity get the whole of the rejected matter from the fish and snails for their 
nutriment, and in consequence of this great supply of food their propagation by runners is very rapid, 
so that I have found it necessary to weed out this vegetable member of the series, and thus prevent it 
from becoming too extended, as I conceived this would interfere with the health of the fish, inasmuch 
as there would consequently be more decaying vegetable matter than the snails present could remove. 
It is true that this might be remedied by increasing the number of snails, which would no doubt effect 
the object, but the increase in those two members of the arrangement must in such a case be continu¬ 
ally going on, so that the removal of the plant is the least troublesome course. Thus in the spring of 
1850 twenty-eight healthy plants were weeded out; and in the spring of 1851 thirty-jive more were 
removed. The prolific growth of this plant may be further illustrated by the observation made during 
the last summer, on the rapid elongation of the silky spiral flower stem, which was found by actual 
measurement to have increased in length fourteen inches during twenty-four hours ; the total extent 
was five feet, and as soon as the flower expanded itself the growth of the stem ceased altogether. At 
present I am attempting the same kind of arrangement with a confined portion of sea water, employing 
some of the green sea weeds as the vegetable members of the circle, and the common winkle or whelk to 
represent the water snails.” 
THE WOODS OF COMMERCE.* 
KILTHOUGH it is our intention chiefly to confine our “ literary notices” to works newly issued 
AA from the press—one great object of such notices being to supply a record of progress—yet in 
the present instance we willingly deviate from that course, for the purpose of calling attention to a 
valuable work, the only one of its kind hitherto produced, and which, although published more 
than eight years since, is still almost quite unknown even to those botanists engaged hi the inves¬ 
tigation of the subject of which it treats. It was only by accident that we recently made acquaintance 
with it; Mr. Holtzapffell, its author, being an exhibitor of woods in the Great Exhibition in Hyde 
* HoltzapffelV s Descriptive Catalogue of Woods, with extensive Botanical Notes by Dr. Boyle. Holtzapffell, Charing Cross. 1843. 
