406 NATURE-PRINTING 



decomposed by the action of the acid, white. It requires but a small quantity of ink, 

 and particular care must be exercised in the rubbing down of the impression. This 

 mode is good as far as it goes, but it is slow and uncertain, and incurs a certain 

 amount of risk, owing to the brittle nature of the object ; and the effect produced is 

 not altogether correct, since it represents those portions black that should be white 

 and those white that should be black. 



The stone not being sufficiently strong to be subjected to the action of a printing- 

 press, an exact facsimile cast, therefore, of it must be obtained, and in such a form 

 as can be printed from. To effect this, tho surface of any such stone (previously 

 treated with fluoric acid), must be extended by embedding it in any plastic com- 

 position that will yield a flat and polished surface, so that the composition sur- 

 rounding the corroded stone will be level with its surface ; all that is necess;iry 

 now is to prepare the whole surface for the electrotype apparatus, by which a perfect 

 facsimile is produced, representing the agate impressed, as it were, into a polished 

 plate of copper. This forms the printing-plate. The ink in this case, as opposed 

 to the mode before referred to, is not applied upon the surface, but in the depres- 

 sions caused by the action of the acid on the weaker parts ; the paper is forced into 

 these depressions in the operation of printing, which results in producing an impres- 

 sion in relief. 



Mr. E. F. Sturges of Birmingham states that, in August 1851, he was engaged in 

 making certain experiments with steel rollers and metal plates for ornamenting 

 metallic surfaces, for which he obtained a patent, sealed in January 1852. He pro- 

 duced plates in lead, tin, brass, and steel from various fabrics, such as wire-lace, 

 .thread-lace, perforated paper, and even from steel engravings, particularly a medal- 

 lion of the Qiieen, from which impressions were printed, and which were distributed 

 among his friepds ; but, that which he did led to no such result as we are at present 

 considering, and nothing more was heard of the subject until the publication of 

 nature-printing in its present state. He, however, also considers himself the un- 

 doubted inventor of nature-printing, notwithstanding what had been done by the 

 experiment of Kyhl in 1833. 



Mr. Aitken too, about this period was occupied in making experiments for the 

 ornamentation of Britannia metal, and also claims the invention, having introduced 

 the use of natural objects, and, as he saj-s, expressly for printing purposes. But 

 Sturges and Aitken only followed Kyhl in their operations, as the one experimented 

 with steel rollers for the purpose of ornamenting metallic surfaces, while the other 

 applied the same to printing purposes, both of which experiments were carried out 

 by Kyhl. 



In the Imperial Printing-Office at Vienna, the first application of taking impressions 

 of lace on plates of metal, by moans of rollers, took place in the month of May 1 852 : 

 according .to Councillor Auer's statement in his pamphlet, it originated in the Minister 

 of the Interior, Eitter von Baumgartner, having received specimens from London, 

 which so much attracted the attention of the Chief Director, that he determined to 

 produce others like them. This led to the use of gutta-percha after the manner that 

 Dr. Branson had used it ; but finding this material did not possess altogether the 

 necessary properties, the experience of Andrew Worring induced him to substitute 

 lead, which was attended with remarkable success. This was, however, only follow- 

 ing in tho steps of Kyhl. Professor Haidinger, on seeing specimens of these laces, and 

 learning the means by which they had been obtained, proposed the application of the 

 process to plants. 



The substitution of lead for gutta-percha was a great step in the process, but would 

 have been insufficient had not the requisite means already existed for producing 

 faithful copies of those delicate fibrous details that were furnished in the examples of 

 the impressions of botanical and other figures in metal. These means consisted mainly 

 in tho great perfection to which the precipitation of metals upon moulds or matrices 

 by electro-galvanic agency has been brought, the application of which more gene- 

 rally known by the name of the Electrotype process was suggested and executed 

 by Dr. Branson in 1851 ; still ho met with no signal success, which may bo attributed 

 to his experiments having been conducted on a limited scale. 



The first practical application of nature-printing for illustrating a botanical work, 

 and which has been attended with considerable success, is to be found in Chevalier 

 Von Heufler's work on the mosses collected from the valley of Arpasch, in Transyl- 

 vania; the second (first in this country}, is & work on the 'Ferns of Great Britain 

 and Ireland,' by Thomas Moore, published under the editorship of the late Dr. Lindlcy. 

 Ferns, by their peculiar structure and general flatness, are especially adapted to 

 develop the capabilities of the process, and there is no race of plants where minute 

 accuracy in delineation is of more vital importance than in that of the ferns; in 

 tho distinction of which, the form of indentations, general outline, the exact manner 



