338 



New Patents and Mechanical Inventions. [May 1, 



at once. These tliiec different modes 



First, l)y three dips and three coueh- 

 ings ; a dip of tlie wiiife pulp being taken 

 in the plain mould, is to be couched ; 

 liien a dip with the water-mark mould 

 is taken of the coloured pulp, and that 

 couched on the white ; and again, a 

 third dip of white in tiie plain mould 

 laid upon this. Tiie layers of each 

 pulp being taken as thin as possible, 

 this completes the formation of the 

 sheet, and the felt is then laid on. The 

 paper tints produced contains a dyed or 

 coloureil layer, with a most brilliant, 

 distinct, and permanent, or indestructi- 

 ble water-mark, between two thin layers 

 of white ; the colour, therefore, is in the 

 heart of the paper, and is scarcely per- 

 ceived until held up to the light. Now 

 it is obviously impossible to place the 

 colour thus in the interior, except in the 

 first formation of the paper. No person 

 can, after the paper is made, dye ihe 

 heart of a sheet of paper without dyeing 

 the exterior also ; nor can there be any 

 test of genuineness devised, whereof the 

 proof can be more simple or self-evi- 

 dent than the having thus merely to 

 ascertain the fact of the colour being in 

 the interior of the paper, by holding it 

 up to the light, and thence deducing 

 tliat this |)aper must have been made 

 imder circumstances scarcely attainable 

 by the forger; or indeed, it may be said, 

 wholly unattainable by him if due atten- 

 tion be paid to the perfection of the 

 manipulations in the original paper; 

 since it would be impossible to produce 

 the triple ])aper in such perfection, 

 without working in large quantities, and 

 by very expensive and cumbrous ma- 

 chinery. 'I'hc second mode of pro- 

 diicing this paper is, by three dippings 

 and two concliings. The triple paper 

 made as above might be objected to for 

 certain banks, on account of its being 

 too tliick. In that case, therefore, this 

 paper may be made, not as above, by 

 three dippings and three concliings, but 

 •with three dippings and only two couch- 

 ings. By dipping fiist in the coloured 

 pulp, then the white upon it in the 

 water-mark mould, then couching both 

 these layers together, which brings the 

 coloured layer uppermost ; then dipping 

 the second white separately in the 

 plain mould, and couching it on the 

 coloured layer. There is also a third 

 mode of producing this paper by three 

 dippings and only one couching. This 

 is cflectcd by dipping first the white, 

 then the colour, and then the white pulp 

 again, one upon the other in the same 

 inould, ami couching the tluce layers 



of combining this paper, give three dif- 

 ferent gradations of substance, whereof 

 the latter is the thinnest, and also the 

 most rapidly made; this latter, how- 

 ever, requires more dexterity in the 

 workman, and is, perhaps, for that rea- 

 son, the best calculated for the desired 

 security, while its thinness places it 

 still further from any spurious imitation 

 that might be attempted, by pasting 

 three sheets of thin ready-made paper 

 together. In those modificafions of the 

 triple paper, where more than one 

 couching are used, a gauge is required 

 in order to place one layer exactly 

 over the other; and, for this purpose, a 

 very simple instrument has been con- 

 trived, being a frame with hinges, to 

 allow it to be raised and thrown back 

 when the felt is laid on, and yet always 

 to fall down on the same spot on the 

 felts; so that, by placing the mould into 

 the angle of this frame, it is sure always 

 to be couched exactly in the same situ- 

 ation, and therefore to place the layers 

 exactly over one another. This frame 

 is further constructed, so that it will 

 rise and fall on two fixed standards, 

 according to the number of felts on the 

 post. The construction of this instru- 

 ment is so simple, that there can be no 

 doubt of any person accustomed to 

 paper-making comprehending it. The 

 test of this triple paper, as it may be 

 termed, may be somewhat strengthened 

 by leaving a margin of the interior 

 coloured layer bare all round one of 

 the faces of the note, which any paper- 

 maker will know may be easily ef- 

 fected, by taking a smaller deckle for 

 the last couching. By thi? means the 

 fact of the colour in the interior appear- 

 ing deeper when looked through than 

 when looked at, is established ; because 

 the colour in this margin, though the 

 same as that in the interior, being super- 

 ficial, appears paler when looked 

 through 5 that is to say, the effect of the 

 superlicially coloured margin is pre- 

 cisely the converse of the colour in tlie 

 centre of the paper, though they are the 

 same tints ; whence it is deduced, that, 

 if that which is superficial looks paler 

 when held up to the light, that which 

 looks darker so viewed must be in the 

 interior; and thus every doubt as to the 

 test is removed by proofs existing in the 

 note itself. 



I have already (says Sir William) 

 described a mode of improving the bril- 

 liancy of the water-mark in white bank- 

 uote paper, by a double layer of colour- 

 less 



