In order to separate B. from milk, recourse is always had to the process of agitation in churns (q.v.). The principle involved in each and all forms of this apparatus is the thorough agitation of the contents, so as to cause the rupture of the minute fat globules present in the milk, and the incorporation of these ruptured fat globules into larger or smaller masses of butter. The cream is strained through cloth into the churn, to remove any foreign matter; and the agitators being set in motion, the friction of the movement, combined with the admission of air, and the chemical changes it induces, raises the temperature of the whole contents. At one time, it was thought that one great object of the agitation was the admission of the oxygen of the air, which becoming thoroughly incorporated with constituents of the milk, combined therewith, and, as a consequence, led to the separation of the butter. It is found, however, that B. can be obtained from milk by mere agitation, without the admission of the oxygen of the air. At the same time, in the ordinary way of churning, oxygen does play a subordinate part by combining with the sugar of the milk, and forming lactic acid, which in its turn sours the milk, and separates therefrom the caseine (q.v.)-cheese-matter-in minute clots or flakes, yielding what is commonly called sour or butter-milk. The process of churning must be conducted at a medium rate. If too quickly performed the B. is soft and frothy, and is said to burst; whilst when too slowly made, it is highly tenacious, strong tasted, and badly flavored. When all the B. has come, which is known by the particles agglutinating into irregular masses, the B. is made by taking the lumps, and well washing and kneading them on a wooden board in a tub of pure spring-water till all the butter-milk has been expressed; it is then divided into the requisite size of lumps, fashioned into rolls, or molded into forms, and usually stamped with some device. In the making up of the B. the hands of the operator must be scrupulously clean, and be free from the. slightest taint of soap. Persons who are subject to moist hands should never knead B., as it is very liable to be contaminated by the slightest foreign matter, especially animal secretions; and it is better always for the operator to wash the hands with water containing some oatmeal before commencing. So important is this source of contamination regarded in America, that every endeavor is made to get quit of manual labor in working the B., and a wooden butter-worker has been invented, and is largely used there. When newly prepared, the B. is called fresh or sweet B., and is of a yellow color, which is well known to be deeper as the pasture on which the cows have been fed is richer, and hence the poorer kinds of B. are often artificially colored with arnotto (q.v.).

A large quantity of the B. sent into market has more or less common salt added, for the purpose of preserving it. For use within a week or two, the proportion of common salt employed is about an oz to 2 lbs. of B., though, where it has to be kept for some time, as much as 1 oz. of salt to 1 lb. of butter is used. The incorporation requires to be carefully and dexterously done, so that the resulting material may be uniform; and the better plan is to add only a portion of the salt at a time, and to knead and re-knead the B. till the whole is thoroughly mixed. When the less amount of salt has been employed, the result is powdered B., and the larger quantity yields salt butter. Much of the latter is closely packed in small wooden firkins or kits, and occasionally in stoneware, and sent into market. Great care must be taken to have these kits, and indeed to have every vessel used in the preparation, as clean or sweet as possible. Constant rinsings with cold water, and scaldings with boiling water, are resorted to. Attention must likewise be paid to the air of the apartments in which the operations are carried on, as a tainted air is very injurious. See illus., DAIRY, vol. IV.,

p. 570.

The adulterations liable to be present in B. are an undue proportion of salt and water, and these run up occasionally to upwards of 33 per cent, or one third of the total weight. Another adulteration is the presence of lactate of zinc, derived from the milk being placed in zinc pails and basins, from the impression that by some imaginary electrical influence an increase in the amount of cream will be the result; but though this is not attained, yet the milk tending to form lactic acid, the latter attacks the zinc vessel, and forms lactate of zinc, which dissolves in the milk, and thereby contaminates it, imparting an unpleasant taste, and, when present in larger quantity, leading to violent spasmodic vomiting. When B. is allowed to get old, it becomes rancid and tastes and smells disagreeably. To some extent an acid is formed, called butyric acid (q.v.). For the use of B. in diet, see FOOD and NUTRITION.

BUTTER, in chemistry, is often applied generically to any substance of the same consistence of B., and is therefore used to designate palm, cocoa-nut, shea, and nutmeg oils. It is also applied to certain metallic substances which have an oily aspect and consistence resembling melted B.; thus we have B. of antimony, bismuth, zinc, and tin.BUTTER of antimony is a thick, dense, oily compound, produced by acting upon the native sulphuret of antimony, SbS,, by concentrated hydrochloric acid, HCl, and heat, when the oily chloride of antimony, SUCls, is formed. See ANTIMONY.

BUTTERINE, or OLEOMARGARINE (q.v.), a substitute for B., was first manufactured in France, but is now extensively produced in other countries, particularly in America. Its sale under the name of Butterine was prohibited in Great Britain in 1887. See Dairy. It is composed of animal fat, amalgamated with milk, to which is sometimes added a small proportion of real butter.

BUTTER, ROCK, a mineral which may be regarded as a variety of alum (q.v.)—an iron alum, appearing as a pasty exudation from rocks that contain alum or its constituents,

Butterfly.

particularly alum-slate and other schistose rocks. It occurs at Hurlet alum-work, near Paisley, Scotland, and in a number of places on the continent of Europe. It is not unlike B. in color, varying from yellowish white to sulphur yellow. It is rather greasy to the touch, and is easily broken in pieces.

BUTTERCUP. See RANUNCULUS.

BUTTERFIELD, JOHN, 1783-1869; one of the founders of the express business in the United States. Before the time of railroads he was proprietor of many important lines of stage coaches, especially in New York state.

BUTTERFIELD, WILLIAM, b. 1814; an English architect noted as a leader of the "Gothic revival" in England. His work has been chiefly in church and collegiate architecture.

BUTTERFISH. See GUNNEL.

BUTTERFLY, the common English name of all the diurnal lepidopterous (q.v.) insects, corresponding with the genus papilio, as originally defined by Linnæus, but forming many genera in the most recent entomological systems. Butterflies exhibit a great similarity in almost all respects to other lepidopterous insects, the common characters of which will be found in the article on that order; but are distinguished even more than the rest of them generally, by brilliancy of coloring, which in butterflies also belongs to the under as well as the upper side of the wings, whilst the beauty of moths and hawk-moths appears chiefly on the upper side. Accordant with this circumstance, is the further peculiarity, that almost all butterflies, when at rest, usually hold their * wings erect, the under side being thus chiefly exhibited; whilst the other lepidopterous insects, when at rest, hold their wings in a horizontal or somewhat inclined position, and some have them wrapped round the body. Butterflies are also the only lepidopterous insects which have no spines, bristles, or hooks on the margins of their wings, by which the second wing on each side can be attached to the first, but both when flying and at rest, have all their wings quite separate. The manner in which the scales of the wings are imbricated, gives those of butterflies a smoother appearance than those of moths and hawk-moths. The antennæ of butterflies are generally simple, slender, and elongated, and terminated by a little club. Their caterpillars have always sixteen feet (see CATERPILLAR). The pupa or chrysalis is angular; is seldom enveloped in a cocoon; is generally suspended by the tail, by means of a silky substance, often to a leaf or twig, but is sometimes supported by bands around the middle; and generally exhibits more or less of that golden coloring from which both the names aurelia (Lat. aurum) and chrysalis (Gr. chrysos) are derived.

Butterflies are found in all parts of the world; they are to be seen during the sunshine of the brief summer extracting nectar from the flowers even of Greenland and Spitzbergen, but they are most numerous in the warmest regions; where, however, many of them live chiefly in the shade of moist foliage, in woods and jungles. Dr. Hooker, describing the scenery on the banks of the Great Runjeet in the Sikkin Himalaya, says that "by far the most striking feature consisted in the amazing quantity of superb butterflies, large tropical swallow-tails, black, with scarlet or yellow eyes on their wings. They were seen everywhere, sailing majestically through the still hot air, or fluttering from one scorching rock to another, and especially loving to settle on the damp sand of the river edge, where they sat by thousands, with erect wings, balancing themselves with a rocking motion, as their heavy sails inclined them to one side or the other, resembling a crowded fleet of yachts on a calm day."

Butterflies possess no small power of wing; some of them, indeed, of which the wings are comparatively thin and delicate, are inferior in this respect, and have a sort of zigzag flight; but others soar in the air with a steady and continuous motion. Shortlived as they are all generally believed to be, some of the tropical species perform wonderful migrations; concerning which, however, nothing but the fact is yet well known. Frequently," says sir James Emerson Tennent in his work on Ceylon, "the extraordinary sight presents itself of flights of these delicate creatures, generally of a white or pale yellow hue, apparently miles in breadth, and of such prodigious extension as to occupy hours and even days uninterruptedly in their passage, whence coming no one knows, whither going no one can tell."

The number of species of B. is very great, and the arrangement of them has been found difficult, chiefly upon account of the great similarity in all important respects which prevails among them all. They are divided, however, into two well-marked sections, of which the first is characterized by having only a single pair of spurs or spines on the tibia (or fourth joints of the legs), placed at their lower extremity; whilst in the other section, the tibia of the hinder legs have two pair of spurs, one pair at each extremity. This distinction, seemingly unimportant in itself, is accompanied by other differences. The second section of butterflies may be regarded as forming a sort of con necting link between butterflies and hawk-moths. A few British species belong to it, but the species are generally tropical, and some of them, found in tropical America, are remarkable for their rapidity and power of flight, and for the migrations which they perform, besides being amongst "the most splendid insects in creation," a resplendent green, inimitable by art, relieving the velvet black of their wings, and varying with

every change of light. The beautiful iridescence of the wings of these and many other butterflies is owing to the peculiar position of the scales.

Some groups of butterflies are remarkable for the imperfect development of the first pair of legs, so that they are generally described as having four legs instead of six. The eggs of butterflies are deposited on the plants, the leaves of which are to supply the food of the caterpillars. In cold and temperate climates, the eggs deposited in autumn are not hatched till the following spring; but it is believed that many species produce several broods in a year, as the eggs in summer may be hatched in a few days. The caterpillars of each species are generally confined to some particular kind of plant, the leaves of which they devour; their ravages are well known, but the excessive increase of their numbers is in part restrained by many enemies, and by none more than by the ichneumons (q.v.) and other insects, which deposit their eggs in them, and the larvæ of which feed on them. An account of B. transformations will be given under INSECT TRANSFORMATIONS.

Butterflies vary in size from less than an inch to almost a foot across the expanded wings. The largest species are tropical. Some of the species are very widely distributed: Cynthia cardui, of which the caterpillar feeds on the leaves of thistles, is found not only throughout Europe, but in Egypt, Barbary, Senegal, Cape Colony, Madagas car, China, Java, Australia, Brazil, and North America, being, in fact, one of the most widely distributed of all insects. The geographical limits of other species appear to be very restricted. The diversity of coloring is almost endless, but a prevalence of certain hues, or of certain modes of the disposal of them, is observable throughout large groups. The caterpillars of many species are variously furnished with spines, those of others-none of them British-have long fleshy prominences, horny at the tip, probably intended as means of defense. The hinder wings of many butterflies are curiously prolonged into tail-like appendages, one or more on each wing, which vary in form, being sometimes long and linear, sometimes broad, and widening to wards the extremity. These are, however, little seen in British species.

Butterflies are chiefly known to us as objects of admiration and of pleasing contemplation, enhancing the charms of the most delightful weather, and always associated with the most lovely scenes, or-it must be added-as a cause of annoyance and vexation by the ravages of their caterpillar young in our fields and gardens. There is, however, one small species (euplaa humata) which affords a supply of food to some of the wretched aborigines of Australia. Butterflies of this species congregate in such vast numbers on the masses of granite in the mountains, that they are collected by simply making smothered fires under the rocks, in the smoke of which they are suffocated. Bushels of them are thus procured, and they are baked by placing them on the heated ground, the down and wings removed, and the bodies made into cakes which resemble lumps of fat. The months of Nov., Dec., and Jan. are quite a season of festivity from the abundance of this food.

Brief notices of a few of the principal kinds of B. will be found in other parts of this work. See CABBAGE BUTTERFLY; for typical form, CAMBERWELL BEAUTY, PURPLE EMPEROR, ETC. See illus., ANTELOPES, ETC., vol. I., p. 510, fig. 16; for LARVA, see adjoining illus., fig. 50.

BUTTERFLY FISH. See BLENNY.

BUTTERFLY WEED, or PLEURISY ROOT, Asclepias tuberosa, see ASCLEPIAS; a plant found in all parts of the United States, and which has obtained a considerable reputation for the medicinal virtues of its root. The root is large, formed of irregular tubers or spindle-shaped branches, externally yellowish brown, internally white, with a somewhat acrid nauseous taste when recent, merely bitter when dried. It yields its properties to boiling water, and is usually administered in the form of a decoction, sometimes in that of a powder. It is diaphoretic and expectorant, and has been found useful in the commencement of pulmonary affections, in rheumatism, and in dysentery.-The stem of the plant is erect and hairy; the flowers orange-yellow.

BUT TERMILK is the form of milk from which the butter or oily matter has been abstracted. See BUTTER. B. contains the caseine, sugar, and salts of ordinary milk, and is only deficient in oily matters. It is therefore nutritious, and is largely used in Ireland and Scotland as an article of food, being very generally partaken of with porridge and with potatoes. It may be drunk ad libitum, is a very agreeable, cooling beverage, and is therefore useful in certain febrile and inflammatory conditions.

BUTTERMILK FALLS, in Le Roy, Genesee co., N. Y., on Oatka creek, which falls over a limestone ledge 90 ft. high. The same name is given to a cascade in Bog Meadow creek, near West Point, N. Y.

BUTTERNUT, or WHITE WALNUT, Juglans cinerea, a large, wide-spreading American tree, with nearly smooth bark, and large leaves. The nuts are well-known, and form agreeable food when dried; when taken green and pickled they are prized for the table. Sugar can be made from the sap, but it is much inferior to that made from maple. The timber is useful for coach and cabinet work, posts, rails, and wooden bowls.

BUTTER TREE, a name given to several tropical trees, of different natural orders, the fruits of which yield concrete fixed oils, having the appearance and used for the pur

BUTTERFLIES, BEETLES, ETC.-1. Pectinate borer. 2. Fiddler. 3. Larva of same. 4. Meal-worm. 5 11. Spanish-fly. 12. Ordemerus. 13. Pea-beetle. 14. Corn-weevil. 15. Vine-weevil. 16. Clov brio. 22. Lady-bug. 23. Bee-eater. 24. Hind-legs of working-bee. 25. Honey-bee queen; 2 chafer. 33. Geometra brumata. 34. Blind-beetle. 35. Little-bellied wasp. 36. Buzz-wasp. 3 42. Larva of same. 43. Pear wasp. 44. Larva of same. 45. Grain-wasp. 46. Swallow-tail. 41 of same. 52. Big-head. 53. Glass-moth. 54. Cone-moth. 55. Willow-weevil. 56. Hornet. gemma. 63. Cabbage-worm. 64. Grape insect. 65. Larva of same. 66. Houey-moth. 67. Fr