A servant of Lewis xv. told me that one day the king his master supping at Trianon with a small party, the talk happened to turn first upon the chase, and next on gunpowder.  Some one said that the best powder was made of equal parts of saltpetre, of sulphur, and of charcoal.  The Duke de la Valliere, better informed, maintained that to make good gunpowder you required one part of sulphur and one of charcoal to five parts of saltpetre.

“It is curious,” said the Duke de Nivernois, “that we should amuse ourselves every day in killing partridges at Versailles, and sometimes in killing men or getting ourselves killed on the frontier, without knowing exactly how the killing is done.”

“Alas,” said Madame de Pompadour, “we are all reduced to that about everything in the world:  I don’t know how they compound the rouge that I put on my cheeks, and I should be vastly puzzled if they were to ask me how they make my silk stockings.”

“’Tis a pity, then,” said the Duke de la Valliere, “that his Majesty should have confiscated our Encyclopaedias, which cost us a hundred pistoles apiece:  we should soon find there an answer to all our difficulties.”

The king justified the confiscation:  he had been warned that one-and-twenty folios, that were to be found on the dressing-tables of all the ladies, were the most dangerous thing in all the world for the kingdom of France; and he meant to find out for himself whether this were true or not, before letting people read the book.  When supper was over, he sent three lackeys for the book, and they returned each with a good deal of difficulty carrying seven volumes.

It was then seen from the article Powder that the Duke de la Valliere was right; and then Madame de Pompadour learnt the difference between the old rouge of Spain, with which the ladies of Madrid coloured their faces, and the rouge of the ladies of Paris.  She knew that the Greek and Roman ladies were painted with the purple that came from the murex, and that therefore our scarlet is the purple of the ancients; that there was more saffron in the rouge of Spain, and more cochineal in that of France.

     She saw how they made her stockings by loom; and the machine
     transported her with amazement.

Everyone threw himself on the volumes like the daughters of Lycomedes on the ornaments of Ulysses; every one immediately found all he sought.  Those who were at law were surprised to see their affair decided.  The king read all about the rights of his crown.  “But upon my word,” he said, “I can’t tell why they spoke so ill of this book.”  “Do you not see, sire,” said the Duke de Nivernois, “it is because the book is so good; people never cry out against what is mediocre or common in anything.  If women seek to throw ridicule on a new arrival, she is sure to be prettier than they are.”