1854.] 



THEEMOGRAPHY. 



31 



and appliances for making tte practice of liandierafts more 

 healtliy. What tliey expect to be sent to tlie Exhibition are, 

 in short, means for working with less injury to the body than 

 at present. Machinery of all sorts may appear, the express 

 object of which is to guard against the myriads of accidents I 

 spoke of, and save lives in numbers to be calculated statistically. 

 Improved hand-tools will be a very valuable department; adzes, 

 which will not divide carpenters' shins, boot-trees which will not 

 obliterate coblers' digestions, &c., may be shown to those most 

 interested in using them. Safer ladders, scaiFolding, chairs for 

 window-cleaning, buckets for lowering men into wells, mines, 

 &c., will save multitudes of industrious souls, if tbe invention 

 of them can be stimulated. Another most important path of 

 discovery is the inventing of substitutes for substances chemi- 

 cally noxious, such as lead, Cjuicksilver, phosphorus, arsenic, 

 the strong mineral acid sand alkalies; or modes of rendeiing 

 their anxious qualities harmless, such, for instance, as fixing 

 the putrid fiimes of decaying matters preserved for manure or 

 making leather. Auotlier interesting department will be that 

 of guards for the organs of sense of the individual workman- — ■ 

 1 mean such as will not interfere at all with present modes of 

 manufacture, but will simply defend the artizan from the in- 

 juries it entails. As examples I have placed on the table a 

 few articles referable to this class sent to us by Sir. Pillischer, 

 of Bond-street. They consist of defences for the eyes against 

 the effect of light, and mechanical injury; and if a third of the 

 contrivances that are furnished to us are as siniple and rational 

 as these, we shall indeed be fortunate. Improved dresses for 

 particular occupations raay fm-nish another department. 



Defences against injury by animals, sucli as safer harness, 

 dog muzzles, &c., would prevent many an accident to a do- 

 mestic servant and working man. 



Such are a few examples of the sort of inventions which the 

 Council trast will be sent for exhibition ; and, considering the 

 position we hold as the friend — equally and impartially — of 

 master and workman; considering our standing with the public, 

 and our widely extended connection with the manuiacturing 

 classes by means of the Institutes in Union, they have a 

 right to expect many more than they themselves can name 



Thermography- 



BY FELIX ABATE, OF NAPLES.* 



This invention constitutes a new art, by means of which 

 natural and artificial objects can be represented and imitated 

 by ]n'inting directly from the objects themselves upon anj' 

 suitable substance. The specimens submitted to the iii.speetion 

 of the Society at its last meeting, are imitations of veneering 

 wood, some simple, and some ornamented with inlaid work, 

 made upon wood, calico, and paper. 



]5eforc entering into the details of this invention, I may 

 perhaps bo allowed to state, in order to prevent mistakes, that 

 it is essentially different from tlic well-known invention under 

 the name of Pliijtogli/plij/, or Nature printing, patented in 

 England by Messrs. Bradbury and Evans, and practiced at the 

 Imperial Printing Office at Vienna, and which consists in 

 taking impressions in lead or other metals, or gutta-percha, 

 from natur.d objects, making electro-plates from such impres- 

 sions, and then printing with these jilates in the usual way. 



* Jourmil of tlie Society of .'Vrtji. 



The principle of my invention dates from an epoch anterior to 

 theGreatLxhibitionofl.S51,a6 Icxhibitedon thatoccasion the 

 fiist specimens of a particular application of it, called 3/e.lulfo- 

 ijruplii/. For this branch of the art I was rewarded with the 

 Prize Medal. An idea of this art will he obtained from the 

 following notice of the principles and processes upon which it 

 rests : 



The art of Metallorjrapliy consists in printing from engraved 

 wood blocks upon mniaUic, siii-faees, so as to produce imitations 

 of figiires and ornaments inlain in wood. This effect is obtained 

 by using, as a printing menstruum to wet the block with, 

 solutions of such metallic or earthy salts as are decomposed 

 when brought into contact with certain metals, and produce, 

 through an electro-chemical action, an adhesive precipitate of 

 a coloured metallic oxide, or any other chemical change upon 

 the metal. Such are the salts of copper, antimony, &c., upon 

 zinc, tin, silver, <ic. ; the hydrosulphuret of ammonia upon 

 copper and brass. 



There arc two principles at work in this branch of the art — 

 the one is the chemical action just referred to ; the other, 

 which is the foundation and the kej'-stone of the invention, in 

 its most general sense, rests in the porousness of the printing 

 object, which causes the absorption of the wetting fluid, and 

 yields it, under the action of pressure, in quantity for each 

 point, proportionate to the capacity of the pores ; so that if 

 any chemical change is wrought upon the impression, to pro- 

 duce a colouring of it, this colouring, by its different shades, 

 makes a true representation of the printing object. 



The application of the invention to printing upon vegetable 

 substances instead of metallic surfaces, required the introduc- 

 tion into the process of some new principle to produce that 

 chemical change which, in metallographj", is spontaneous. I 

 devised, for that pui-]3ose, two principles, which, by different 

 means, lead to the same results. One of these principles I bor- 

 rowed from the art of dyeing. It consists in the peculiar ac- 

 tions that the salts, acids, and alkalies have upon each other, and 

 upon vegetable colouring matters. It is upon these actions the 

 processes of mordantand discharge printing on textile manufiic- 

 tures rest. The surface of the printing object is slightly wetted 

 with the acting fluid, which is then well wiped ofi' from the 

 surface; the impression is then taken, which, by combining 

 w-th a previous or a subsequent dyeing of the printed surface, 

 instanfcineonsly appears. The other princijile 1 found in heat, 

 that is, in the colouring action that this most powerful agent 

 of Nature h.as upon vegetable substances when acted on by 

 acids, which colouring I believe, is the effect of an accelerated 

 carbonization of the surfaces of these substances produced by 

 the acid. I think I may properly call this art THEUMOGR.VMlY, 

 or the art of printing by heat. 



From the following description of the process, it will ho 

 remarked — perhaps with some degree of surprise — the exces- 

 sive sensitiveness of vegetable substances under the joint action 

 of acids and heat, so that an infinitesimal dote of the former, 

 and an instantaneous application of the latter, are sufFicicnt to 

 produce the nmst striking effects. The process is as follows : — 



Suppose a sh.;et of vcnecring-wood bo llie object froni 

 which imjire.ssions aire to be taken ; I ex]Hisf the wood for a 

 few minutes to the cold evapoi-.ition of hydrochloric or sulphuric 

 acid, or I slightly wet it with either of these acids diluted, and 

 then well wipe the acid oH' from the surface. Afterward.'* it is 

 laid upon a piece of calico, or paper, or ciiniu\on wood, and by 

 a stroke of the press an imiirc^.-icn is taken, which is, of coun^e, 

 quite invisible, but bv i'\)Mi.--iMg llii.-* impn>sii.!), inmicdiatcly 



