Ostrich feathers may be bleached either by exposure to the vapour of sulphurous acid, or by immersion in a solution of hydrogen peroxide; the latter method is the better one, but more expensive; the sulphurous acid may weaken the feathers. The feathers should first be immersed for several hours in a solution of carbonate of ammonia (about 3 oz. to 1 gallon of water), then washed in a warm bath made from white curd or Castile soap, passed through clean soft water, and then put in the hydrogen peroxide bath (1 part to 10 nai-ts of water), removed, washed again in water, dried slowly, and curled. Instead of the hydrogen peroxide, a bath containing barinm peroxide in solution and dilute sulphuric acid may be employed, but in this case the last washing must be thorough, or the feathers will be very tender. A pure white may be obtained by afterwards passing the feather through a warm s.>ap bath with a little blue powder stirred in. Feathers may be dyed immediately after bleaching, or. for dark colours, without bleaching, treating them first with carbonate of ammonia to soften them.