for four consecutive years; memorandum-books for keeping journals. Skeleton maps, ruled in squares. Note-books. _Clothing._--This item is a very important part of the outfit of the explorer. I was more afraid to be without shoes than anything else, for if the worst came I could have made garments with the skins of goats, gazelles, or antelopes. Clothing of wool is of no value whatever in the jungle. After a few hours nothing but shreds would be left. Twill goods which are strong are the best. These should be of dark blue, which become lighter in color as they are washed. No coats, but a certain kind of blouse, as here represented, of very strong material, just as strong as the trousers, with many pockets, etc. The shirts must be of gray flannel, just like our common shirts. This avoids underwear. Panama hat with high crown, in which you can put green leaves or wet towels when going in the sun. I learned how to make soap by boiling ashes, then using the water that had been boiled, and mixing with palm-oil or some other oil, and boiling these two together. In many tribes I had to do my own washing, for the natives, who rubbed their bodies with clay and oil or powder of colored wood, did not know what dirt was. Oh, how I used to hate washing-day! One must have an outfit of needles of different sizes. These I kept in quicksilver salve, otherwise they become useless in a few days on account of the rust. No neck-ties. One hundred pairs of lace boots, these coming above the ankles, with no high heels, and soles not too thick, so that they may bend when jumping from the root of one tree to another. The nails were of copper, for, as I have said before, iron gets rusty so quickly in the great forest; forty-eight pairs of strong twilled trousers; forty-eight flannel shirts; ten dozen pairs socks. Such is the outfit friend Paul had with him. [Illustration] PHOTOGRAPHING A FLASH LIGHTNING. Having your camera all ready, the apparatus pointing out of the open window of your room, which room must be the uppermost one in your house, how are you going to manage so as to catch a picture of the lightning? Theoretically, the photographing of a star does not seem so difficult; practically, however, innumerable precautions are necessary. Astronomical photography has got the matter down very fine. Your camera follows automatically the movement of the stars, but it is a mechanism which requires great delicacy in perfecting, and which costs several thousands of dollars.