326 Procecdings of Societies. 
8. The mode of development of the racheole does not favour the view of 
Lindley ; according to which it ought to have for its point of origin the 
axil of one of the two bracts constituting the utriculus. 
9. The utriculus is an organisation analogous to that of the vaginiform 
bract which we observe at the base of the axis of inflorescence. 
10. All the observations I have made are in favour of the theory of 
Kunth, and contrary to that of Lindley.”’ 
II.—Photoglyphic Engraving of Ferns ; with Remarks. 
By H. Fox Tatgot, Esq., LL.D. (Plate VI.) 
Dr Talbot remarked—This plate, representing a fern leaf, is done by 
the process which I have called photoglyphic engraving, and which was 
published a few years ago in the various photographical journals. It 
consists in covering a plate of steel or copper with a film of gelatine 
mixed with bichromate of potash, placing the object, in this instance a 
fern leaf, upon the plate, and exposing it to sunlight for a minute, then 
removing the object, dusting the plate with finely powdered resin, to give 
a grain to the engraving, melting the resin, and when the plate is cold 
brushing it with acamel’s-hair brush dipped in perchloride of iron, which 
speedily penetrates the parts upon which the light has not acted, and 
effects an etching, while the parts exposed to sunshine are thereby ren- 
dered impermeable to the etching liquid. Such a plate (steel), thus pre- 
pared, is capable of yielding at least five thousand impressions. It 
will be remarked that the leaf exhibits no venation. This arises from 
its being a dried specimen from the herbarium ; but recent specimens, 
especially of Adiantum, Trichomanes, Hymenophyllum, &c., yield en- 
gravings with a very beautiful venation. Grasses also succeed remark- 
ably well, and one of the most curious objects when engraved is the 
feathery achenes of Leontodon Taraxacum (the common dandelion), 
which are so well given as sometimes to be almost deceptive, except that 
the achenes themselves are apt to come out too black to be natural. If 
printed in pale brown ink, I think they would have a strong resemblance 
to nature. I wished to have shown a plate of this description to the 
Botanical Society, but the occurrence of cloudy weather for several days 
in succession has prevented my doing so on the present occasion. 
If this art had been invented a hundred years ago, it would have been 
very useful during the infancy of botany, when communications with dis- 
tant countries were so difficult. It would have been easy for botanical 
travellers such as Thunberg, Aublet, Loureiro, &c., to have taken with 
them a small printing-press, and to have worked off a small edition of 
fifty copies of each engraving they made, and sent the copies home to 
Europe whenever an occasion presented itself. Some of the copies would 
doubtless have escaped shipwreck and come to the knowledge of Kuropean 
botanists. Supposing the engraving only represented a leaf and a flower 
of each plant described in the works, it would have greatly aided modern 
botanists in determining the plants intended by those authors, whose de- 
scriptions are frequently so incorrect that they are like so many enigmas, 
and have proved a hindrance and not an advantage to science. 
I1l.—List and Localities of Rare Plants found in the vicinity of Perth. 
By Mr Joun Sim, A.B.S. Ed. 
