We have at first some difficulty in realising how he police could know the contents of an obscure author’s desk.  For one thing we have to remember that Paris, though it had been enormously increased in the days of Law and the System (1719-20), was still of a comparatively manageable size.  In 1720, though the population of the whole realm was only fourteen or fifteen millions, that of Paris had reached no less a figure than a million and a half.  After the explosion of the System, its artificial expansion naturally came to an end.  By the middle of the century the highest estimate of the population does not make it much more than eight hundred thousand.[44] This, unlike the socially unwholesome and monstrous agglomerations of Paris or London in our own time, was a population over which police supervision might be made tolerably effective.  It was more like a very large provincial town.  Again, the inhabitants were marked off into groups or worlds with a definiteness that is now no longer possible.  One-fifth of the population, for instance, consisted of domestic servants.[45] There were between twenty-eight and thirty thousand professional beggars.[46] The legal circle was large, and was deeply engrossed by its own interests and troubles.  The world of authorship, though extremely noisy and profoundly important, still made only a small group.  One effect of a censorship is to produce much gossip and whispering about suspected productions before they see the light, and these whispers let the police into as many secrets as they choose to know.

In Diderot’s case, his unsuspecting good-nature to all comers made his affairs accessible enough.  His house was the resort of all the starving hacks in Paris, and he has left us more than one graphic picture of the literary drudge of that time.  He writes, for instance, about a poor devil to whom he had given a manuscript to copy.  “The time for which he had promised it to me expired, and as my man did not appear, I became uneasy, and started in search of him.  I found him in a hole about as big as my fist, almost pitch-dark, without the smallest scrap of curtain or hanging to cover the nakedness of his walls, a couple of straw-bottomed chairs, a truckle-bed with a quilt riddled by the moths, a box in the corner of the chimney and rags of every sort stuck upon it, a small tin lamp to which a bottle served as support, and on a shelf some dozen first-rate books.  I sat talking there for three-quarters of an hour.  My man was as bare as a worm, lean, black, dry, but perfectly serene.  He said nothing, but munched his crust of bread with good appetite, and bestowed a caress from time to time on his beloved, on the miserable bedstead that took up two-thirds of his room.  If I had never learnt before that happiness resides in the soul, my Epictetus of Hyacinth Street would have taught it me right thoroughly."[47]