If you wish to represent a tempest properly, observe and set down the effects of the wind blowing over the face of the sea and of the land, raising and carrying away everything that is not firmly rooted in the general mass. And in order properly to represent this tempest, you should first of all show the riven and torn clouds swept along by the wind, together with the sandy dust blown up from the seashore, and with branches and leaves caught up and scattered through the air, together with many other light objects, by the power of the furious wind. The trees and shrubs, bent to the ground, seem to desire to follow the direction of the wind, with branches twisted out of their natural growth, and their foliage tossed and inverted. Of the men who are present, some who are thrown down and entangled with their garments and covered with dust should be almost unrecognisable; and those who are left standing may be behind some tree which they embrace, so that the storm should not carry them off. Others, bent down, their garments and hair streaming in the wind, should hold their hands before their eyes because of the dust. Let the turbulent and tempestuous sea be covered with eddying foam between the rising waves, and let the wind carry fine spray into the stormy air to resemble a thick and all-enveloping mist. Of the ships that are there, show some with rent sails, whose shreds should flap in the air, together with some broken halyards; masts splintered, tumbled, with the ship itself broken by the fury of the waves; some human beings, shrieking, and clinging to the wreckage of the vessel. You should show the clouds, chased by the impetuous wind, hurled against the high tops of the mountains, wreathing and eddying like waves that beat against the cliffs. The air should strike terror through the murky darkness caused by the dust, the mist, and the heavy clouds. _To Learn to Work from Memory_ If you want properly to commit to your memory something that you have learnt, proceed in this manner--namely, when you have drawn one object so often that you believe you can remember it, try to draw it without the model, after having traced your model on a thin sheet of glass. This glass you will then lay upon the drawing which you have made without model. Observe well where the tracing does not tally with your drawing, and wherever you find that you have gone wrong, you must remember not to go wrong again. You should even return to the model, in order again to draw the wrong passage until it shall be fixed in your memory. And if you have no level sheet of glass for tracing, take a very thin sheet of goat-parchment, well oiled, and then dried. And after the tracing has done service for your drawing, you can efface it with a sponge and use it again for another tracing. _On Studying in Bed_