The word "flocculent" is used of many substances which have a fleecy or "flock"-like appearance, such as a precipitate of ferric hydrate.
It dissolves readily in water and the aqueous solution decomposes on standing; a dark-brown flocculent precipitate of azulmic acid, C 4 H 5 N 5 0, separating whilst ammonium oxalate, urea and hydrocyanic acid are found in the solution.
Another aphis of importance is the woolly aphis (Schizoneura lanigera) of the apple and pear: it secretes tufts of white flocculent wool often to be seen hanging B D E humuli).
By means of the calamistrum the silk secreted by the cribellum is teased into a fine thread which is twisted round the main threads of the web, giving it a very characteristic woolly or flocculent appearance.
Sometimes it is woolly and flocculent, sometimes smooth like parchment, and its shape depends in a large measure upon the habits of the female towards her offspring.
The number of cercariae produced by the pullulating rediae in a single water-snail is immense, and as they are emitted at a given period or a few successive periods, the snail at these times appears enclosed in a cloud of whitish flocculent matter.
Thus a strip of zinc plunged into a solution of silver sulphate, containing not more than 0.03 gramme of silver in the litre, becomes covered with a flocculent precipitate which is a true alloy of silver and zinc, and in the same way, when copper is precipitated from its sulphate by zinc, the alloy formed is brass.
Coccus pinicorticis causes the growth of patches of white flocculent and downy matter on the smooth bark of young trees of the white pine in America.
When kept for some time in sealed tubes it changes to a yellowish liquid, from which a yellow flocculent substance gradually separates, and finally it suddenly solidifies to a dark red mass, which appears to be a polymeric form.
But about 7% showed an exceedingly limited coagulation, in which the clot was colourless and flocculent, and confined to the heart.
0-Naphthol, C 1 oH 7 OH, prepared by fusing sodium 0-naphthalene sulphonate with caustic soda, crystallizes in plates which melt at 122° C. With ferric chloride it gives a green colouration, and after a time a white flocculent precipitate of a dinaphthol.
Manganous Carbonate, MnCO 3, found native as manganese spar, may be prepared as an amorphous powder by heating manganese chloride with sodium carbonate in a sealed tube to 150° C., or in the hydrated form as a white flocculent precipitate by adding sodium carbonate to a manganous salt.
By using hot acid the yellow anhydrous tungstic acid is precipitated, which is insoluble in water and in all acids except hydrofluoric. It may be obtained in a flocculent form by exposing the hexachloride to moist air.
Cupric hydroxide, Cu(OH) 2, is obtained as a greenish-blue flocculent precipitate by mixing cold solutions of potash and a cupric salt.
It is a soft, flocculent powder, which on sublimation forms transparent, monoclinic crystals.
Arsenides, Arsenites, &c. - Several iron arsenides occur as minerals; lolingite, FeAs 2, forms silvery rhombic prisms; mispickel or arsenical pyrites, Fe2AsS2, is an important commercial source of arsenic. A basic ferric arsenite, 4Fe2O3 As2O3.5H 2 O, is obtained as a flocculent brown precipitate by adding an arsenite to ferric acetate, or by shaking freshly prepared ferric hydrate with a solution of arsenious oxide.
Ferrous sulphate and sodium carbonate in the cold give a flocculent precipitate, at first white but rapidly turning green owing to oxidation.