I carried a 10 oz book, “The Wild Muir” on my recent (June 2018) backpack into the Trinity Alps. I find quite a contrast between my 18 lb, 5 night load, and what John Muir carried into much wilder country.
“Many hikers and climbers know of John Muir’s minimalist approach to preparing for a wilderness adventure. When he set off to walk from Indiana to the Gulf of Mexico, “I rolled up some bread and tea in a pair of blankets with some sugar and a tin cup and set off.””
“Muir never lived off the land,” reports historian Michael P. Cohen. “Since he wasn’t a hunter or fisherman, he was frequently hungry.”
“When asked what kind of bread he took to the mountains, Muir replied, “Just bread.” At his home in Martinez, California, he’d buy sourdough at an Italian bakery. In Yosemite, he’d secure French bread at Black’s Hotel, or soda bread from Degnan’s. Sometimes he would bake cakes of unleavened flour over the coals. His preference, however, was “feeding on God’s abounding, inexhaustible spiritual beauty bread.””
“On excursions into the back country of Yosemite, he traveled alone, carrying “only a tin cup, a handful of tea, a loaf of bread, and a copy of Emerson.”[31]:52–53 He usually spent his evenings sitting by a campfire in his overcoat, reading Emerson under the stars.” Apparently he sometimes considered the overcoat a burden to be left behind; he once spent the night on Mt Shasta in a storm without the overcoat.
It seems he, or probably people in general, were tougher in those days, around 1875.

