xl 
European Ferns. 
and fourteen in number) which accompany the work. These plates are executed by the 
process known as nature-printing — an invention which was first brought into use in 1853 by 
Alois Auer, an Austrian, state printer, although it is claimed by Denmark to have been 
invented more than twenty years previously by Peter Kyle, a goldsmith of Copenhagen. The 
process is simple enough : the object from which the impression is desired to be taken being 
placed between two smooth-polished plates, one of copper, the other of lead, these are then 
drawn through a pair of rollers, under great pressure, and, on being separated, it is found that 
a perfect impression of the object has been made on the leaden plate. When only a few 
impressions are required, this may be used as an engraved plate ; but, on account of its 
softness, it is usual to obtain a facsimile of it in copper by electrotype, which is used as the 
printing plate. In England the art was taken up by Mr. Henry Bradbury, who produced by 
it not only the illustrations to the work now under notice, but also “ The Nature-printed 
Seaweeds ” — a very beautiful book. It is obvious that no figures can be more strictly 
accurate than those thus obtained from the objects themselves ; but it of course results 
that the representation is that of an individual, and thus does not convey that idea of a 
species as a whole which is given by the drawing of a botanical artist. There is a rigidity, 
too, about the ferns to which we are more especially referring in these remarks which is 
scarcely in harmony with subjects which owe so much to the grace and elegance of their 
general outline. We have to acknowledge much help and many useful suggestions which 
we have derived from the pages of “The Nature-printed Ferns,” especially with reference to 
some of the more interesting and distinct variations of certain species. 
But this is far from being Mr. Moore’s only contribution to the literature of British 
ferns ; indeed, he has written many separate works upon them, all being thoroughly good and 
trustworthy. The only one to which we will refer, however, on the present occasion, is the 
exceedingly compendious and handy little volume entitled “ British Ferns and their Allies,” 
which is an abridgment of another work by the same author — “The Popular History of 
British Ferns.” It is intended as an introduction to the study, and contains full descriptions 
of all the species, with a figure of each, and references to the more important varieties. 
The exceedingly low price at which it is issued brings it within the reach of all ; other fern- 
books have been issued at the same charge (one shilling), but they are not to be compared 
with this for extent of information or practical utility. Mr. Moore’s most important contribution 
to the general literature of ferns unfortunately remains incomplete; this is the “Index Filicum,” 
of which the first part appeared in 1857. It contains a synopsis of the characters and arrange- 
ment of the tribes and genera, each genus being illustrated by a woodcut showing its 
characteristic features, and a list of the species known ; the synonymy is very copiously given, 
as is also the geographical distribution. Although, as has been said, imperfect, it is, so far as 
it goes, a most useful work, and it is much to be regretted that its publication has been sus- 
pended. Speaking of the geographical distribution of ferns reminds us of Fyell’s admirable 
little volume, “The Geographical Handbook of all known Ferns,” published in 1870, to which 
we have already referred at page xv. In this is brought together all the most recent information 
up to the date of publication regarding the geographical distribution and detailed localities of 
ferns, the localities being grouped primarily under the great divisions of the globe, and secondarily 
under divisions of somewhat less extent, as we have already shown at the page above cited. 
For British county distribution of ferns Mr. II. C. Watson’s works, especially his invaluable 
“Compendium of the Cybele Britannica,” should be consulted; more detailed localities will be 
found in Mr. Moore’s “Nature-printed Ferns” above mentioned. 
