To travel into the unknown is to court disaster, and few set out without carefully organizing their equipment. Therefore ship, crew, instruments, all these things are selected only after the most cautious consideration. Neither too much nor too little of anything must be taken. On such a journey through an unknown land, and one in which so-called natural conditions so powerfully play the part of enemy, where Nature seems to defy one to pluck out the heart of her mystery, everything must be done to anticipate all emergencies. Even when we have prepared everything with the greatest care accidents will still threaten the safety of our expedition. We shall need enough of everything and not too much; therefore it is not a matter of money - although enough money is certainly necessary. [...] We make these provisions after we have made our plan. That is the most difficult part of the work, for once made we must follow it to the end, while at the same time seizing the fresh opportunities as they present themselves. Now that we are ready to start, consider for one instant what it is we are setting out to do. We are about to make a dagerous and very difficult expedition into the unknown to bring you back a few visible proofs of the known. We are not to bring back the idea itself, but only its fringe; for to return from the unknown with the idea itself would certainly make you think we were mad, whereas to bring back hints of the idea satisfies you as to our sanity.