1818.] and on the Composition of the Ink. 369 



appears to be dry. An effervescence is produced, and when it 

 ceases, the stone is gently washed with pure water. 



While the stone is in this state, and still moist, printers' ink is 

 applied to it, with ihe common apparatus, which only adheres 

 to the parts that are dry. A sheet of paper, properly prepared 

 to receive the impression, is then laid upon the stone, and the 

 whole is subjected to the action of the press, or the cylinder. 

 To retain the design upon the stone, and to preserve it from 

 dust, when it is not used immediately after being prepared, it is 

 covered with a stratum of a solution of gum arabic, and this 

 varnish is removed by water, when we wish to print from the 

 stone. 



Instead of ink, a peculiar kind of pencil is sometimes employed 

 to draw upon the stone, or upon paper, from which a counter- 

 impression is taken on the stone. The pencils are composed of 

 the following ingredients melted together : three parts of soap, 

 two parts of tallow, and one of wax. When the whole is melted 

 and well mixed, we add lamp-black, until the colour be sufficiently 

 intense ; the fluid is then run into moulds, where it becomes 

 solid as it cool*, and acquires the consistence necessary for the 

 formation of pencils. 



Additional Observations on Lithography. 



The following particulars are, for the most part, extracted 

 from a report on this interesting art made to the Royal Institute 

 of France, and published in the Journal de Physique for Feb. 

 1817. 



Aloys Sennefelder, a chorus singer at the theatre of Munich, 

 was the first who observed that certain calcareous stones have 

 the property of contracting an intimate adhesion to characters 

 traced on their surface with thick oily ink, and that, if the stone 

 was afterwards moistened, and then dabbed with printers' ink, an 

 impression of the characters might be transferred to paper. In 

 180U he obtained from the King of Bavaria a patent for his 

 process, and first applied it to printing music. The histoiy of 

 the further progress of this art is foreign to the object of the 

 present notice. 



The only stone hitherto discovered which completely answers 

 the purpose, is a compact, nearly pure carbonate of lime of a 

 greyish white colour. At Solenhofen, near Pappenheim, in 

 Bavaria, are extensive quarries of it ; also at Kehlheim, near 

 Ratisbon, at both which places it has for many years been 

 raised, and made into flag-Stones for floors and hearths, &c. an 

 application to which it is well fitted by its easily splitting into 

 lamina! of the required thickness avid area, and by the facility 

 with which it is brought to a smooth surface. It is supposed to 

 be the same rock, geologically speaking, as the while lias, a 



Vol. XI. N°V. 2 A 



