Francesco Pico, prince of Mirandola, a small territory about 30 Italian miles west of Ferrara, afterwards absorbed in the duchy of Modena, was born on the 24th of February 1463. The family was illustrious and wealthy, and claimed descent from Constantine. In his fourteenth year Pico went to Bologna, where he stud1ed for two years, and was much occupied with the Decretals. The traditional studies of the place, however, disgusted him; and he spent seven years wandering through all the schools of Italy and France and collecting a precious library. Besides Greek and Latin he knew Hebrew, Chaldee and Arabic, and his Hebrew teachers (Eliah del Medigo Leo Abarbanel and Johanna Aleman—see L. Geiger Johann Reuchlin (1871), p. 167) introduced him to the Kabbalah, which had great fascinations for one who loved all mystic and theosophic speculation. His learned wanderings ended (1486) at Rome, where he set forth for public disputation a list of nine hundred questions and conclusions in all branches of philosophy and theology. He remained a year in Rome, but the disputation he proposed was never held. The pope prohibited the little book in which they were contained, and Pico had to defend the impugned theses (De omni re scibili) in an elaborate Apologia. His personal orthodoxy was, however, subsequently vindicated by a brief of Alexander VI., dated 18th June 1493. The suspected theses included such points as the following: that Christ descended ad inferos not in His real presence but quoad effectum; that no image or cross should receive latreia even in the sense allowed by Thomas, that it is more reasonable to regard Origen as saved than as damned; that it is not in a man’s free will to believe or disbelieve an article of faith as he pleases. But perhaps the most startling thesis was that no science gives surer conviction of the divinity of Christ than “magia” (i.e. the knowledge of the secrets of the heavenly bodies) and Kabbalah. Pico was the first to seek in the Kabbalah a proof of the Christian mysteries and it was by him that Reuchlin was led into the same delusive path
Pico had been up to this time a gay Italian nobleman; he was tall, handsome, fair-complexioned, with keen grey eyes and yellow hair, and a great favourite with women. But his troubles led him to more serious thoughts, and he published, in his 28th year, the Heptaplus, a mystical exposition of the creation. Next he planned a great seven fold work against the enemies of the Church, of which only the section directed against astrology was completed. After leaving Rome he again lived a wandering life, often visiting Florence, to which he was drawn by his friends Politian and Marsilius Ficinus, and where also he came under the influence of Savonarola. It was at Florence that he died on the 17th of November 1494. Three years before his death he parted with his share of the ancestral principality, and designed, when certain literary plans were completed, to give an ay all he had and wander barefoot through the world preaching Christ. But these plans were cut short by a fever which carried him off just at the time when Charles VIII. was at Florence.
Pico’s works cannot now be read with much interest, but the man himself is still interesting, partly from his influence on Reuchlin and partly from the spectacle of a truly devout mind in the brilliant circle of half-pagan scholars of the Florentine renaissance.
His works were published at Bologna in 1496 by his nephew, Giov. Fran. Pico, with a biography, which was translated by Sir Thomas More as Life of John Picus, Earl of Mirandola, in 1510. See the essay in Walter Pater’s Renaissance (1878); and the study by J. Rigg, prefixed to the reprint of More’s Life in the “Tudor Library” (London, 1890).
PICRIC ACID, or Trinitrophenol, C6H2·OH·(NO2)3 [1·2·4·6], an explosive and dyestuff formed by the action of concentrated nitric acid on indigo, aniline, resins, silk, wool, leather, &c. It is the final product of the direct nitration of phenol, and is usually prepared by the nitration of the mixture of phenol sulphonic acids obtained by heating phenol with
concentrated sulphuric acid (E. Eisenmann and A. Arche,
Eng. pat., 4539 (1889). It may also be obtained by
oxidizing the symmetrical trinitrobenzene with potassium
ferricyanide in alkaline solution (P. Hepp, Ann. 1882, 215,
p. 352). It Crystallizes from water in yellow plates melting at
122·5° C., which sublime on careful heating, but explode when
rapidly heated. It is poisonous and possesses a bitter taste,
hence its name from the Greek πικρός, bitter. It has a strongly
acid reaction, being almost comparable with the carboxylic
acids. By the action of bleaching powder it is converted into
chlorpicrin, CCl3·NO2. Phosphorus pentachloride converts
it into picryl chloride, C6H2Cl(NO2)3, which is a true acid
chloride, being decomposed by water with the regeneration of
picric acid and the formation of hydrochloric acid, with ammonia
it yields picramide, C5H2NH2(NO2)3. Silver picrate and methyl
iodide yield the methyl ester, which gives with ammonia
picramide. Picric acid forms many well-defined salts, of a
yellow or red-brown colour. It also yields crystalline compounds
with many aromatic hydrocarbons and bases. It imparts a
yellow colour to wool and silk. The chief application of picric
acid and its salts is in the manufacture of explosives. When
ignited, picric acid burns quietly with a smoky flame, and it is
very difficult to detonate by percussion, its salts, however, are
more readily detonated. The more important picric powders
are melinite, believed to be a mixture of fused picric acid and
gun-cotton; lyddite, the British service explosive, and shimose,
the Japanese powder, both supposed to be identical with the
original melinite; Brugère's powder, a mixture of 54 parts of
ammonium picrate and 45 parts of saltpetre, Designolle’s powder,
composed of potassium picrate, saltpetre and charcoal, and
emmensite, invented by Stephen Emmens, of the United States.
It may be detected by the addition of an aqueous solution of potassium cyanide, with which it gives a violet-red coloration, due to the formation of isopurpuric acid R. Anschutz (Ber., 1884, 17, p. 439) estimates picric acid by precipitation with acridine.
PICRITE (from Gr. πικρός, bitter, because these rocks are
rich in magnesia, a base which forms bitter salts), a rock belonging
to the ultra basic group, and consisting mainly of olivine
and augite often with hornblende and biotite and a greater or
less amount of plagioclase felspar. The picrites are of
“hypabyssal” origin and in their natural occurrence are
connected with dole rites (diabases and teschenites). The
distinction between them and the peridotites, which have an
essentially similar composition, is not easy to denne, but the
peridotites accompany the true plutonic rocks, such as gabbro,
norite and pyroxenite, are often very coarsely crystalline, and
form large bosses and laccolites, while the picrites usually are
found in sills or intrusive sheets.
In hand specimens the picrites are dark green to black; the absence or scarcity of lath-shaped plagioclase felspars distinguishes them from diabases and they rarely have the lustre-mottling which is a characteristic of the peridotites. Since they contain much olivine they readily decompose, passing into deep green and brown incoherent masses in which are embedded rounded lumps of harder consistency. They have a high specific gravity (about 3·0) and may be distinctly magnetic, because they are rich in iron ores. Porphyritic structure is rare though occurring sometimes in the rocks known as picrite-porphyries, the phenocrysts are olivine and augite. There is seldom any fine-grained or glassy ground mass, and the typical microstructure is holocrystalline, moderately fine grained and somewhat poikilitic. Olivine is abundant in rounded pale green crystals. It may form one half of the rock but rarely more than this. The augite is generally brown or reddish-brown, sometimes violet, and tends to enclose the olivine, yielding poecilitic aggregates. Brown hornblende often occurs as marginal growths around the pyroxene, and may be so abundant as to replace augite to a large extent; rocks of this class are known as hornblende-picrites. Bright green or pale-green hornblende are less frequently present, and in many cases are really of secondary origin. Deep brown biotite is a frequent accessory mineral and both biotite and hornblende sometimes enclose olivine. A small amount of basic plagioclase occurs in many picrites; apatite, iron oxides, chromite and spinels are minor ingredients seldom altogether absent.
