Before trying to explore a cavern it is advisable to study the topography of the surrounding country. Note where the main stream of the district lies. Its level determines how deep the cave can possibly go. The thickness of the limestone bed above that level shows the maximum possible altitude of the cave chambers.
Most of the caves that have been explored are entered through a passage into a hillside. Such an opening usually indicates that this was once the drainage outlet of the cave. If no water be running out of it now, the underground stream must have worked a way down through the original cave bed and opened a new gallery below.
A novice should first gain some experience in company with a guide, in some cave that is easily entered. Everybody is nervous on his first expedition underground, unless the course is well known to companions who have been there before. A cavern is the worst of all places to get "rattled" in. When you do start exploring on your own account, take it gradually, until you can bore into the unknown as coolly as you would bite off the end of a cigar.
When a new cave is to be entered, do not go with a large party. They will confuse each other with their reverberating babble, discussions as to the best route will arise, and the larger the party the greater the chance that someone will flunk. Three is a good number: then there are two men to help one who may have got into difficulties.
The importance of thoroughly dependable lights is paramount. Big, clumsy lanterns should not be taken; they are always a nuisance when one is climbing or crawling. The best light for cave exploration that I know of is an acetylene lantern with small bail, shaped like a conductor's lantern, giving a 20-candle-power light for five to six hours on three ounces of carbide. It spreads light all around, instead of merely throwing a beam in one direction like a bull's-eye lantern. If one such light is in the party the others may be small acetylene bull's-eye lamps. The best of these has a sparking attachment that lights without matches (but don't leave out the matches), and is fitted with folding handles on the side. The hook and spring attachment used on miners' lamps may be substituted, but personally I do not like it so well.
Spare carbide to last at least twelve hours should be carried by each man, in air-tight tins specially made for the purpose; and everybody should have a canteen of water, both for the lamp and for his own use, as there is no certainty of finding any in an unexplored cave.
See that the lanterns are in perfect working order. If previously used a good deal, they should be refitted with fresh felt packing, as the old packing may be clogged with carbide dust.
Besides his lantern, every member of the party should carry one or two good hard candles. There is no telling when an accident may happen to a lantern ; it may balk, may be crushed, or may be dropped into a pit. The candle is also needed when recharging the lantern.
Matches should be waterproofed, either by dipping in melted paraffin, or in collodion, or in shellac varnish thinned with alcohol. An emergency supply of matches not to be used except when there are no others, should be carried in a waterproof box with cover fitted so it cannot drop off. This match-box ought to have a small swivel or eye attached so it can be fastened to one's belt by a key chain. Then it will stay with you to the death. Inside this box, vvith the matches, stow a little strip of emery cloth, folded, to strike a match on when you and all your surroundings are sopping wet.
A compass may be useful if the general course of the cave is fairly straight, but in the labyrinths that most caves are contorted into it is of little or no avail. Neither is a pedometer. A pocket aneroid may be useful to indicate one's depth from the surface, but it is by no means necessary.
Wear old clothes, of course. Everything" should be of wool, except that the coat should be of conventional hunter's pattern, khaki or duxbak, with plenty of pockets. Such a coat carries all the impedimenta except the lantern, and keeps them stored away where they will not flop nor stick out to irr> pede one's progress in climbing or in squeezing through narrows. Wear the flaps closed at all times.
The hat should be soft and with narrow brim. Gloves are useful to keep the hands from being lacerated. Shoes should be studded with cone-headed Hungarian nails (not calks nor broad hobnails) around the edges of heels and soles, including the arch of the foot. This makes them cling better to the rocks. Too many nails defeat the purpose, for they will not "bite" well. Hard steel calks are slippery on rocks.
Waterproofs are an utter nuisance in cave hunting. The wetting you may get will do you no harm at all in the cave air, which is always of uniform temperature. Do not wear a lot of bunchy clothing from dread of cold. You will be exercising all the time in the most exhilarating air you ever breathed. Go slow in entering and emerging from the cave; then there will be no risk of a chill.
Take for granted that the cave will prove to be a labyrinth of three dimensions, far more puzzling than anything you have ever encountered on earth. It may not be so; but most caverns are. There is only one absolutely safe way to explore an unknown cave, so far as not getting lost is concerned, and that is for each member of the party to carry plenty of common white twine, and take his turn as fde closer in paying out this twine as he advances. In some places you can buy cord put up in tubes that unreels itself without danger of tangling. Where the going is good there may be no need for the twine; but don't neglect this simple precaution in all parts of the cave where there may be the least doubt of the route back again.
Someone should carry a strong cord for lowering a lantern into pits or gulfs.