In preparing the stone to take the picture extreme care has to be exercised, for so great is its affinity for grease that even a finger-mark will become perpetuated. After a drawing on the stone is finished it is a precaution to coat it with a solution of gum-arabic and nitric acid, which fills up the pores of the stone in the unfilled parts and prevents the drawing from spreading. [Illustration: FIFTEENTH STONE--LIGHT RED.] [Illustration: SIXTEENTH STONE--DARK GREY.] Having described the manner in which the picture on stone is prepared, we now come to the printing of it. To begin with, there is the "proving-press," which is employed in preparing the stones for the machine. The gummy solution is first washed off, but sufficient remains in the pores of the stones to offer a resisting influence to the ink when the time for printing comes. At this stage the stone is damped and a roller charged with printing ink is passed over its surface, every part of the design being brought in contact with the ink. Accidental grease spots are removed by scraping, polishing, or the application of acid, otherwise they would develop and spoil the result. [Illustration: SEVENTEENTH STONE--GOLD.] [Illustration: EIGHTEENTH STONE--LIGHT GREY.] When the stone is thus rectified it is subjected to what is technically termed etching; that is, a weak solution of gum and nitric acid is applied, which causes the surface of the bare part of the stones to be gently eroded, and gives a stronger "tooth" to the design. Although the ink of the design itself may now be washed away and the picture be invisible, yet it is there, ready to receive any desired colour which forms the part of the picture. The stones have to be damped and inked before each impression is taken, but nevertheless the printing proceeds with great rapidity, ranging from six hundred to one thousand impressions per hour. [Illustration: THE FINISHED CHROMO-LITHOGRAPH: "THE MADONNA ANSIDEI" (AFTER RAPHAEL).] _Sadi the Fiddler._ AN INCIDENT IN THE SIEGE OF STRASBURG. BY MAX PEMBERTON. Sadi the fiddler, carrying the little black case under his arm, locked the door of his garret as carefully as though it had contained the wealth of the Cæsars. It was the night of Monday, the twenty-first day of September, in the year 1870. Sadi had not tasted food for twenty hours, and, though he well understood that there was very little to eat in the town of Strasburg, he went forth bravely in quest of it. After all, someone might throw him a bone, even though he were nothing more than a poor, crazy fiddler.