PARCHMENT PARIS BASIN. 



725 



the books of Aristotle themselves. Parchment is 

 like an easy man, who is always of the same opinion 

 as the last speaker. 



The preparation of parchment is by no means a 

 pleasant or cleanly operation. Our readers may, 

 probably, have seen carts loaded with sheep-skins 

 proceeding from large markets, or in the vicinity of 

 slaughter-houses. These skins are bought of the 

 butcher by the parchment-maker, in order to pre- 

 pare, from them, the material in which he deals. 

 The skins are first stripped of their wool, which is 

 sold to the wool merchant, who prepares it for the 

 making of cloth, &c. They are then smeared 

 over with quick-lime on the fleshy side, folded once 

 in the direction of their length, laid in heaps, and 

 so left to ferment for ten or fifteen days. 



The skins are then washed, drained, and half 

 dried. A man, called the skinner, stretches the skin 

 upon a wooden frame. This frame consists of four 

 pieces of wood, mortised into each other at the 

 four angles, and perforated lengthways from distance 

 to distance, with holes furnished with wooden pins 

 that may be turned like those of a violin. The 

 skin is perforated with holes at the sides, and 

 through every two holes a skevver is drawn; to this 

 skewer a piece of string is tied, as also to the pins, 

 which being turned equally, the skin is stretched 

 tight over the frame. The flesh is now pared off 

 with a sharp iron tool, which being done, the skin 

 is moistened and powdered with fine chalk : then, 

 with a piece of flat pumice-stone, the remainder of 

 the flesh is scoured off. The iron tool is again 

 passed over it, and it is again scoured with chalk 

 and pumice-stone. The scraping with the iron 

 tool is called draining; and the oftener this is 

 done, the whiter becomes the skin. The wool or 

 hair side of the skin is served in a similar manner; 

 and the last operation of the skinner is to rub fine 

 chalk over both sides of the skin with a piece of 

 lambskin that has the wool on: this makes the 

 skin smoother, and gives it a white down or knap. 

 It is left to dry, and is removed from the frame by 

 cutting it all round. 



The parchment-maker now takes the skin thus 

 prepared by the skinner. He employs two instru- 

 ments; a sharp cutting tool, sharper and finer than 

 the one employed by the skinner ; and the summer, 

 which is nothing more than a calf-skin well stretched 

 upon a frame. The skin is fixed to the summer ; 

 and the parchment-maker then works with the 

 aharp tool from the top to the bottom of the skin, 

 and takes away about one half of its thickness. 

 The skin being thus equally pared on both sides, it 

 is well rubbed with pumice-stone. This operation 

 is performed upon a kind of form, or bench, covered 

 with a sack stuffed with flocks; and this process 

 leaves the parchment fit for writing on. 



The paring of the skin in its dry state upon the 

 summer, is the most difficult process in the whole 

 art of parchment-making; and is only entrusted to 

 experienced bands. The summer sometimes con- 

 sists of two skins, and then the second is called 

 counter summer. The parings and clippings of the 

 skin in the preparation of parchment are used in 

 making glue and size. 



Parchment is sold in rolls of twenty skins each. 

 The term roll is also employed in law. It is de- 

 rived from the Latin Rotulus, a schedule of paper 

 or parchment rolled up into a cylindrical form. 

 The English probably derived their law term roll 

 from the French rolle; because legal instruments 

 written on pirchment were sewed or glued to- 



gether, and thus rolled up, whence comes the verb 

 to enrol. 



Vellum is a kind of parchment made from the 

 skins of young calves: it is finer, whiter and 

 smoother than common parchment, but prepared in 

 the same manner, except that it is not passed through 

 the lime pit. 



Parchment is coloured for the purposes of bind- 

 ing, &c. The green dye is prepared from acetate 

 of copper (verdigris), ground up with vinegar, with 

 the addition of a little sap green. Yellow dye is pre- 

 pared from saffron ; a transparent red from brazil 

 wood ; blue from indigo, ground up with vinegar ; 

 black from the sulphate of iron and solution of 

 galls. Virgin parchment, which is thinner, finer, 

 and whiter than any other kind, and used for 

 fancy work, such as ladies' fans, &c., is made of 

 the skin of a very young lamb or kid. 



Parchment forms a considerable article of French 

 commerce. It is made in most of the cities of 

 France, and vast quantities of it are imported into 

 England, Flanders, Holland, Spain, and Portugal. 



PARIS BASIN. This was the first tertiary 

 formation minutely examined, and the researches 

 of Cuvier and Brongniart in this locality gave a 

 new impulse to, and introduced a new era in geo- 

 logical science. .The area called the Paris Basin, 

 extends in length to 180 miles from north-east to 

 south-west, and about 90 miles from east to west. 

 This space is a great depression in the chalk, which 

 has been filled up by alternating groups of marine 

 and fresh water strata. Cuvier enumerates the fol- 

 lowing groups : 



( Plastic clay. 

 ( Signite. 

 (.First sandstone. 

 Calcttire grossier. 



JSilicious limestone. 

 Gypsum, with bones of ani- 

 tion, i mals. 



v. Fresh water marls. 

 '"Gypseous marine marls. 



1. Fresh water formation, 



2. First marine formation, 



4. Second marine formation, 



Upper marine sands and sand- 



stones. 



Upper marine marls and lime- 

 stones. 

 rSilicious millstone without 



5. Third fresh water formation J gjjjgjjj; m ni st one, with shells. 

 (. Upper fresh water marls. 



Cuvier supposed that these formations had been 

 at successive periods deposited over the chalk, and 

 that, consequently, the land had been alternately 

 submerged and elevated above the waters of the 

 ocean. Subsequent investigations of Prevost and 

 others have demonstrated, however, that in all 

 probability the strata were deposited in a gulf, at 

 one extremity of which the sea entered ; and at the 

 other a large river, while other streams may have 

 flowed in at different points, and thus gave rise to 

 the alternating mixture of marine and fluviatile 

 remains, which are ever found associated to- 

 gether. 



The Plastic Clay, No. 1, and marls, are found 

 both in the upper and lower beds, and contain 

 fresh water shells, lignite, and drift wood, evidently 

 the deposit of a large river entering the basin. 

 This deposit, as might be expected, is of partial 

 extent throughout the area of the basin. 



The Calcaire Grassier, No. 2, is a coarse lime- 

 stone, often passing into sand, such as may partly 

 have been derived from the debris of the subjacent 

 chalk. It contains 400 distinct species of shells, 

 both marine and fluviabile ; many of these are 

 greatly comminuted, but others are entire and per- 

 fect. Of these, 137 species are of the genus 



