70 ANNUAL OF SCIENTIFIC DISCOVERY. 







reproduced from some old printed pages. It is scarcely known yet how 

 many centuries may elapse ere the ink of old books becomes so dry that it 

 cannot be transferred by the new process; but it is quite certain that a 

 couple of hundred years does not so far dry it as to render it incapable of 

 giving an impression, so that we may have the earliest folio copies of Shak- 

 speare's plays reproduced with exactness, in more available sizes, through 

 the medium of a few sheets of India-rubber. Once-a- Week. 



COPYING-PAPER. 



Copying-paper, into the body of which a certain proportion of protosul- 

 phate of iron (copperas) has been introduced, either during the manufacture 

 or afterwards, by passing it between rollers covered with felt impregnated 

 with a solution of salt, is much more advantageous in use than the com- 

 mon paper. A letter written with common ink containing an infusion of 

 nutgalls, or having the tanno-gallate of iron for its base, and covered with 

 the above copying-paper, gives, by means of the press, a perfect fac-simile. 

 If a little sugar or pro-gallic acid is added to the ink, a good copy may be 

 had by pressing lightly the copying-paper upon the latter without the use of 

 the press, taking only the precaution to interpose between the hand and the 

 sheet of copying-paper another sheet of oiled paper, over which the rubbing 

 must be done. Cosmos. 



NEW METHOD OF PRINTING MUSIC. 



A new method of engraving and printing music has been introduced at 

 Paris. It is analogous to the method of carving wood by burning the pat- 

 tern in. The music is stamped into blocks of wood with heated stamps, 

 which have a shoulder to insure their penetrating to an equal depth. From 

 this block a stereotype cast is taken. An edition of fifteen hundred copies, 

 if stereotyped and printed by this method, is said to cost only about one- 

 third as much as if engraved and printed from the engraved plate. 



S. W. FRANCIS' WRITING-MACHINE. 



This machine is placed in a neat, portable writing-case, about two feet 

 square and ten inches deep, which may be carried about and used on any 

 ordinary table. It is worked by means of keys placed on a key-board like 

 those of a piano, each key representing a letter of the alphabet, and each 

 letter producing its impression at a common centre. An endless narrow 

 tape stretches the full length of the " bed " of the machine, passing over a 

 small roller at either end, and uniting underneath. This tape is saturated 

 with the ink. 



Directly in the centre of the " bed," and under the tape, is a circular hole 

 of one inch diameter. Over this hole, and under the tape, on a car, a sheet 

 of paper is placed;, then a sheet of tissue paper directly over it, leaving the 

 tape between the two sheets of paper. A delicate frame then falls upon the 

 paper, which keeps it in place, and moves while the printing progresses. 



A short steel rod then falls from a suspended arm, so as to present a flat 

 surface, or platin, in the centre, directly over the paper. The lids being 

 raised from the keys, they are played upon as in a piano, each being let- 

 tered from A to Z, with the various punctuation marks, etc. The numbers 



