No arithmetic is sufficient to reckon the number of gnats that torment this country, as no patience is equal to enduring them. Wherever you go, they afflict your ears with their noise, and your flesh with their stings, making you wish for a hundred arms to drive them away. During cold weather, they remain quietly in their lurking-holes, but when the sun is hot and the air tranquil, they fly out in search of food, and are never more ferocious than at dawn or twilight. Where the grass is high, where bushes, pools, rivers, or marshes are near at hand, and where there are thick woods which exclude the air, there you will be plagued by vast numbers of serpents, and swarms of gnats. If you have to pass the night in such a situation as I have described, never dream of sleeping. After the fatigue of riding or walking the whole day, you will fruitlessly weary both hands at night with driving away gnats. Unable to sleep, how often have I reproached the sun with returning too slowly! I pitied the horses which, after being debilitated with toil and fasting, were surrounded by such a swarm of hungry gnats, that, as they could neither take any rest, nor graze the herb, they stood round the fire to inhale the smoke, which, if rather sharp, will keep off those trumpeting insects. Gnats cannot endure the smoke of cow-dung; but besides that it will have the same unpleasant effect upon your own nostrils, if your sense of smelling be not very dull indeed; you will hardly meet with cow-dung in the woods, where there is not so much as the shadow of a cow, and travellers through these deserts are too much laden with provisions, water, and fuel, to be able to carry bundles of it with them. I was much pleased with the ingenuity of a Negro, who, when he slept on a journey, always had at his side some resinous material from rotten wood, which glistens at night, smokes gently without any unpleasant smell, and, as I observed, always defended him from gnats. Incredible is the annoyance caused by these insects in a long journey. We have often returned home mangled, swollen, and bloody, in short, so unlike ourselves, that we could hardly know one another. Even in the house, if you do not wish to pass a sleepless night, you should not suffer the door or window to remain open at sun-set, especially when you light a candle; for they fly by swarms to any light, whenever they can find access to it. There is a species of gnats which are smaller, but more mischievous than the common kind; for though they have not the disagreeable hum of the others, they creep into the mouth, ears, and nose, and sting violently.