1855.] on Nature-Printing, HI 



precaution, especially with respect to placing the cylinders exactly 

 parallel, and at the same time at a proper distance, and to have the 

 plate to be stamped carefully burnished and polished ; besides, the 

 utmost care must be used, as particles of dust or dirt would be 

 printed together with the object itself. Moreover, care must be 

 taken, that the rolling of the plates is managed well, so as to run 

 parallel, without deviating from their first direction. 



" Leaves that are to be printed must first be spread upon a clean 

 sheet of paper and placed upon a warm oven ; a second sheet put 

 over them is to be strewn with sand, and the whole left to dry 

 under a weight. This done the leaves are taken out with due 

 precaution, and placed for a quarter of an hour into water. They 

 are dried again in the same way, and this manipulation is repeated 

 four or five times. By this means I always found that the leaves 

 gained in tenacity and firmness, that they lost all their moisture, 

 and became more fit to be stamped. Objects, such as laces, weavings, 

 figured ribbons, and such like, can be printed without any prepara- 

 tion, provided they be spread flat between the plates. 



" The season being very unfavourable for gathering good strong 

 leaves, I had to overcome many difficulties, so that the copies are 

 not so good as they might have been — for I have observed that 

 leaves obtained from green-houses do not yield such distinct prints 

 as those that grow in the open air, when properly developed."* 



It would appear from the practical hints here given that Peter 

 Kyhl was no novice at the process. lie distinctly points out what 

 he conceives to be its value, by the subjects that he tried to copy ; 

 and he enters into detail on the precautions to be observed in the 

 operation of impressing metal plates so as to ensure successful 

 impressions. His manuscript explains that he had experimented 

 with copper, zinc, tin, and lead plates. Still there existed obstacles 

 which prevented him from making a practical application of his 

 invention. In the case of zinc, tin, and copper, the plant, from the 

 extreme hardness of the metals, was too much distorted and 

 crushed ; while in lead, though the impression was as perfect as 

 could be, there was no means of printing many copies, as it was not 

 possible after the application of printer's ink to retain the polished 

 surface that had been imparted to the lead plate, or to cleanse it so 

 thoroughly as to allow the printer to take impressions free from dirty 

 stains. This was a serious obstacle, which was not compensated for 

 even by the peculiar rich surface of the parts that were impressed, 

 attributable to the lead being more granular than copper, and which is 



♦ This allusion to the want of tenacity and firmness in young, and especially 

 in green-house plants, is quite consistent with the experiment made at the 

 present time. Mr. Bradbury stated, that to obtain an impression at all, upon 

 a plate of metal, of a plant, it was indispensable that the plant should be 

 thoroughly dried and free from sap ; otherwise the plant would spread in all 

 directions, without leaving any visible indentation. Objects such as lace, and 

 figured fabrics, can be impressed without any preparation, provided they be 

 spread flat between the plates. 



Vol. II. I 



