The altitude was now about 16,000 feet, but at the foot of a steep little rise the arrieros stopped again. This time they succeeded in unloading two mules before we could scramble down over the sand and boulders to stop them. Threats and prayers were now of no avail. The only thing that would satisfy was a legal document! They demanded an agreement "in writing" that in case any mule or mules died as a result of this foolish attempt to get up to the snow line, I should pay in gold two hundred soles for each and every mule that died. Further, I must agree to pay a bonus of fifty soles if they would keep climbing until noon or until stopped by snow. This document, having been duly drawn up by Professor Coello, seated on a lava rock amidst the clinker-like cinders of the old volcano, was duly signed and sealed. In order that there might be no dispute as to the time, my best chronometer was handed over to Pablo Tejada to carry until noon. The mules were reloaded and again the ascent began. Presently the mules encountered some pretty bad going, on a steep slope covered with huge lava boulders and scoriaceous sand. We expected more trouble every minute. However, the arrieros, having made an advantageous bargain, did their best to carry it out. Fortunately the mules reached the snow line just fifteen minutes before twelve o'clock. The Tejadas lost no time in unloading, claimed their bonus, promised to return in ten days, and almost before we knew it had disappeared down the side of the mountain. We spent the afternoon establishing our Base Camp. We had three tents, the "Mummery," a very light and diminutive wall tent about four feet high, made by Edgington of London; an ordinary wall tent, 7 by 7, of fairly heavy material, with floor sewed in; and an improved pyramidal tent, made by David Abercrombie, but designed by Mr. Tucker after one used on Mt. McKinley by Professor Parker. Tucker's tent had two openings--a small vent in the top of the pyramid, capable of being closed by an adjustable cap in case of storm, and an oval entrance through which one had to crawl. This opening could be closed to any desired extent with a pucker string. A fairly heavy, waterproof floor, measuring 7 by 7, was sewed to the base of the pyramid so that a single pole, without guy ropes, was all that was necessary to keep the tent upright after the floor had been securely pegged to the ground, or snow. Tucker's tent offered the advantages of being carried without difficulty, easily erected by one man, readily ventilated and yet giving shelter to four men in any weather. We proposed to leave the wall tent at the Base, but to take the pyramidal tent with us on the climb. We determined to carry the "Mummery" to the top of the mountain to use while taking observations.