It is the ordinary Bleaching powder of commerce and is quite unstable, hence old preparations, unless sealed, are of little value.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
In the old days, before the news of evil travelled fast, the widowed wife would live for days, weeks, months, unclouded by the knowledge of her loneliness, rejoicing in the coming hour that was to bring her wanderer back; and even as her heart laughed to think how now, at last, the time was drawing near for his return, his heart had ceased to beat, and, it may be, his bones were already Bleaching where the assassin's knife had left him in the desert; or were swaying to and fro in perpetual monotonous response to the ground-swell, in some strange green reflected light of a sea-cavern no man's eye had ever seen; or buried nameless in a common tomb with other victims of battle or of plague; or, worst of all, penned in some dungeon, mad to think of home, waking from dreams of her to the terror of the intolerable night, its choking heat or deadly chill.
"Somehow Good"
William de Morgan
They found that the meadows had become Bleaching grounds, so that the cows had to go elsewhere to get their dinner, and that this white area was all linen.
"Dutch Fairy Tales for Young Folks"
William Elliot Griffis