PIOKERSGILL PICRIC ACID 499 lished " Races of Man and their Geographical Distribution " (4to, Philadelphia, 1848 ; repub- lished in London in Bohn's "Illustrated Li- brary," 1850) ; " Geographical Distribution of Animals and Man " (Boston, 1854) ; and " Geo- graphical Distribution of Plants" (1861). In 1858 he communicated to the American orien- tal society an essay on the "Invention of the Art of Writing," and read before the Boston natural history society an essay on "The Sting- ing Power of the Physalia." PICRERSGILL. I. Henry William, an English painter, born in London, Dec. 3, 1782, died there, April 25, 1875. In 1826 he was elected a royal academician, and in 1856 became libra- rian of the academy. He painted the por- traits of a great number of distinguished per- sons, among others that of Robert Vernon, the donor of the Vernon gallery, which is in the South Kensington museum. II. Frederick Rich- ard, a painter, nephew of the preceding, born in London in 1820. His first work, "The Brazen Age," in water colors, was exhibited in 1839. For his cartoon of the " Death of King Lear" he received a prize of 100 at the ex- hibition in Westminster hall in 1843. He also received in 1847 one of the three first class prizes of 500 for his colossal oil painting of the "Burial of Harold," purchased for a simi- lar sum for the house of lords. Among his im- portant works are "Samson Betrayed" (1850), "Love's Labor Lost" (1855), and "Corsairs throwing Dice for their Prisoners" (1867). In 1847 he was elected an associate of the royal academy, and in 1857 an academician. PICKLES, vegetables of various sorts, as small cucumbers, onions, string beans, and cab- bage, and also some fruits, such as melons, peaches, India mangoes, and soft unripe nuts, preserved in vinegar to be eaten as a condi- ment. The articles are steeped or parboiled in brine and then transferred to the vinegar, to which some salt is added, and some of a vari- ety of spices are also introduced, as well as mustard, horse radish, &c. East India pickles are flavored with curry powder mixed with mustard and garlic. For some articles the vinegar is used cold, for others hot, and for onions pure distilled vinegar is employed in order that their natural whiteness may be pre- served. The use of pickles is so general that they arc almost one of the common necessaries of life; and among seafaring men especially their consumption is prodigious. They are often contaminated with a poisonous salt of copper, which is intentionally introduced to give them a pleasant bright green color. To obtain this effect the vinegar is boiled in brass or copper vessels, or copper coins are intro- duced into the boiling liquid, and sometimes verdigris and blue vitriol or the sulphate of copper. This salt is produced by boiling vine- gar which contains sulphuric acid in copper vessels, and most of the vinegar that is used in the pickle factories is of this character. Dr. Hassall reports that 23 samples of pickles ex- amined by him all contained copper to some extent, and two or three of them in dangerous quantities. Sulphuric acid also was detected in 19 out of 20 samples of vinegar used for pickling. Numerous fatal cases of poisoning are reported as having occurred from the use of such pickles. The presence of copper may be suspected in all pickles of a brighter green color than the vegetables naturally possess; and it is proved when a bright piece of iron immersed for a short time in the liquid be- comes coated with copper ; or if, when a bit of the pickles is minced fine and put into a vial with liquid ammonia diluted with an equal amount of water, the liquid becomes blue, it is owing to the presence of copper. PICO BELLA MIRANDOLA. See MIRANDOLA. PICOT, Francois Edonard, a French painter, born in Paris in 1786, died there, March 15, 1868. He studied under Vincent, and obtained in 1813 the first great prize of the school of fine arts for his picture of " The Death of Jacob," which enabled him to spend several years in Rome. After his return to Paris he exhibited "The Death of Sapphira" and "Amor and Psyche," and several allegorical paintings for the Louvre. In 1830 he was appointed paint- er to the government, and executed various works at Versailles, of which the best known are his portrait of Talma and " The Entrance of the Duke of Guise into Calais." In 1836 he was elected to the academy of fine arts. PICOU, Henri Pierre, a French painter, born in Nantes, Feb. 27, 1824. He studied under Delaroche. His best known works are " Cleo- patra spurned by Octavius " (1853) ; " Love at Auction," and " The Harvest of Love " (1855) ; " The Night of Cleopatra," and " The first Kiss" (1867); "Moliere at Versailles," "The Bath," and " Moses on the Banks of the Nile " (1870) ; and " Psyche in the Lower Regions," and " The Night Watch " (1873). PICRIC ACD) (Gr. Ta/cpdf, bitter ; ^ called also carbazotic, trinitrophenic, and nitrophenisic acid), a frequent product of the action of nitric acid upon complex organic substances. Carbolic acid, salicine, coumarine, phloridzine, silk, indigo, and a variety of resins yield it when treated with fuming nitric acid. The most economical raw material is the tar oil which distils over between 302 and 392 F. It can also be conveniently made from carbol- ic acid. In preparing it on a large scale, Grace Calvert allows 7 Ibs. of carbolic acid to fall drop by drop into 42 Ibs. of nitric acid of spe- cific gravity 6'52. After the lapse of about 36 hours, the whole of the carbolic acid having been introduced, heat is applied, and the acid liquor is concentrated to one fourth of its bulk ; on cooling it becomes solid. It is dis- solved in water and allowed to crystallize. Picric acid crystallizes in long, pale, yellow, brilliant, rectangular plates, soluble with diffi- culty in cold, readily in hot water, and also soluble in alcohol, ether, and benzole. The acid has an intensely bitter taste, which has
