882 KEPORT— 1 900. 



theoretical or technical form, for in both processes the knowledge of the expert 

 is demanded ; but its province is to lessen, and, in some instances, dispense with, 

 the monotonous manual labour necessitated by the present system. There are larjje 

 areas of point paper in elaborate designs to which the same weave effect has to be 

 applied, and where some labour-saving device is much needed. Further, in the 

 enlargement of the artist's sketch to scale there is much mechanical work that it 

 ought to be possible to reduce. The photographic inventions of Szczepanik profess 

 to accomplish these objects, and the designs submitted prove that there are 

 possibilities of succfss in certain styles of pattern. A new field for experiment 

 has been discovered, the extent of which it is not possible to forecast, but it may 

 reasonably be anticipated that the genius and temerity of the disco vei'er will prove 

 equal to its more complete exploration. 



The essential purpose of Szczepnnik's invention is to develop from the ordinary 

 sketch and enlarge to a prescribed scale the technically prepared design, marked 

 with the thousands, or may be millions, of dots grouped in different orders and so fitted 

 together as to impart precise definition to the several portions of the woven figure 

 or design. The process is threefold, consisting (1) of the preparation of the ruled 

 paper ; (2) the development of the design from an ordinary photographic negative ; 

 and (.3) the application of the weave units to the several parts of the figure. 

 Primarily the apparatus consists of an optical lantern with a suitable arrangement 

 of lenses. One important factor is the ' raster ' or multiplying plate, containing 

 some 435,600 perforations, through each of which the weave type passes, and is 

 printed on the enlarged design. In addition there are weave- plates for determin- 

 ing the details of the pattern, and small metal slides for producing particular 

 sections in distinct forms of type, so that they may be as readily distinguished 

 from each other as if sketched in various colours. 



The light from the lantern passes through the negative of the design, entering 

 a pair of lenses between which is fixed the small metal plate of the proper shape 

 for developing the marks on the sensitised pHper. The process consists in dividing 

 and subdividing the ' scale ' pattern into rectangular spaces, and of marking each 

 with the correct weave type. When there is no negative in the lantern this type 

 is repeated as many times as there are holes in the ' raster,' showing the 

 feasibility of marking every square photographically on any kind of weaver's 

 paper. 



In the first place, the negative is made of the complete design, and all parts 

 erased but the ground sections, allowing of these being printed with their supple- 

 mentary weave elements. Negatives of every part of the pattern are similarly 

 printed in succession until the entire design has been obtained. For the production 

 of shaded work, e.g. portraits and pictorial subjects, selecting plates are employed. 

 These secure an accurate graduation of tones perfectly in harmony with the 

 photograph from which they are derived. Provision is made for the execution of 

 patterns in compound as well as in single structure fabrics ; but it follows, the more 

 complex the build of the texture, the more intricate the process of design produc- 

 tion. Certain textile designs may evidently be produced photographically by the 

 Szczepanik system, so that it is now a question for demonstration whether 

 designs so produced are comparable in legibility and equal for all practical 

 purposes — as forcible in detail, as vit^l in execution — to those prepared by the 

 much slower hand method. 



4. Shop Buildings. By E. R. Clark, M.Inst.C.E. 



5. The Internal Architecture of Steel, ^y Professor Arnold. 



A New Form of Calorimeter for measuring the Wetness of Steam. 

 By Professor J. Goodman. 



