1824.] [ 337 ] 



NEW PATENTS AND MECHANICAL INVENTIONS. 



To Sir William Congreve, of Cecil- 

 slreet. Strand; for certain Improve- 

 ments in the 3Ianvfacture of Bank- 

 note Paper, for the Prevention of 

 Forgenj.— Dec. 4, 1819. 



1"1HE object of lliis iiivtiilion is to 

 , form certain tests of genuineness 

 in llie paper on wliiclj bank-notes are 

 <o be printed, wliioli cannot be imitated 

 after the paper is made, as is at present 

 tlie case with the ordinary paper used 

 for bank-notes; but whicii tests or dis- 

 tinguishing marks or peculiarities must 

 indispensably be given to the paper in 

 its original construction or furaiation at 

 the paper-mill, which no ordinary 

 forger can accomplish, so that no for- 

 gery can be completed without the aid 

 of paper-makers. And the object is, 

 moreover, to make these tests or marks 

 as simple as they can be, so that they 

 may be immediately recognised and un- 

 derstood by the most unlearned persons, 

 that all orders of jjeoplc may be equally 

 able to distinguish a bad note from a 

 good one, by observing whether the said 

 losts exist or not in any note that may 

 be offered. Of these tests, and of the 

 mode of producing them, there are 

 various modifications and gradations. 



First, the very texture, smoothness, 

 and thinness, of bank-paper, united with 

 a new and peculiar degree of strength, 

 and with a peculiarly transparent water- 

 mark, so bright that it cannot be imi- 

 tated, either by friction, pressure, or 

 varnish, may be made to form a test of 

 genuine bank-paper, which can only be 

 imitated in the original fabrication of 

 the paper, and not subsequently. This 

 smoothness and thinness are to be ac- 

 complished by a particular process in 

 preparing the material, by mashing or 

 rubbing the pulp to pieces instead of 

 cutting it, by which the pulj) is made of 

 a fine long and llakey staple instead 

 of a short nature, so that the texture of 

 the paper becomes tough and elaslic 

 instead of being weak and brittle; this 

 property also may be increased by the 

 mixture of certain transparent vege- 

 table and animal substances, such as 

 gum, isinglass, [larchment-cuttings, and 

 the like, by whicli a |)cculiar degree of 

 lenacilj and transparency is attainable, 

 and the due proportions of whicli can 

 best bo regulated by the experiment of 

 the workmen. 'I'his paper, when 

 dipped singly, will afford a much more 

 Jbrilliant water-mark than ordinary 

 paper, liom the uulurc of the materials, 



which may be augmented by forming 

 the water-mark of very thin sheet cop- 

 per or brass, instead of wire, or by 

 mixing both. The water- mark, how- 

 ever, of such single colourless paper, 

 cannot be made permanently indelible. 

 To accomplish this most desirable cud 

 therefore in white paper, by which a 

 certain test may be obtained in such 

 paper of its not being a forged water- 

 mark, this paper must be dipi^ed in a 

 vat of the thinnest possible material 

 twice for once touching it ; and the 

 transparency and distinctness of the 

 water-mark will be improved by dipping 

 the mould in clear water between the 

 first and second dips in the pulp, by 

 which means a permanent difference of 

 thickness between the substance of the 

 water-mark and of the plain part is cre- 

 ated, whereas the ordinary water- mark 

 is little more than an impression on the 

 surface of the paper. A note thus pro- 

 duced, though it need not, with the fine 

 materials proposed, be thicker than an 

 ordinary note, will, on the whole, bo 

 much stronger than the common note, 

 because it will, in fact, be more close or 

 dense in its texture, though not thicker. 

 The tests of the genuineness of the 

 white bank-note paper which he thus 

 manufactures, are indeed extremely de- 

 licate and beautiful, but they are not of 

 the same decidedcharacter and univer- 

 sal manifestation as those which f shall 

 proceed to explain. 



These are formed by the introduction 

 of a coloured layer of pulp, in combina- 

 tion with white layers, and are thus 

 effected. The material being prepared, 

 and reduced into the finest possible 

 pulps, as above staled, a mineral dye is 

 added to one of them, or a vegetable dye 

 will answer if the pulp be made of 

 material previously dyed. Thus he has 

 found the Adrianople red cloth form 

 a most excellent coloured pulp, not only 

 because the colour is peculiarly clear 

 and permanent, but because it is a dye 

 most difficult to give. The pulps being 

 thus prepared, the following different 

 modifications of this paper may be made, 

 for the purpose of giving the test or 

 mark required, and which is certainly 

 not to be imitated, but by a similar pro- 

 cess to tiiat of the original manufacture. 

 'J'his pajier should be made in two dif- 

 f(;rcnt moulds, one a plain one and the 

 other with a water-mark, cither as 

 above of thin copper-plate, or wire, or 

 both, as follows. 



I'irst, 



