AFFIRMATION AFFRE. 159 decomposition. If chlorine and hydrogen gases be mixed in the dark they will not unite, but exposed to light they combine at once ; while in every green vegetable leaf carbonic acid is decomposed every day under the influ- ence of solar light. The recent investigations in photography have greatly multiplied the number of substances over which light is known to exert a chemical influence. Elec- tricity also has a governing action over affinity. An electric spark, shot through a mixture of oxygen and hydrogen gases, causes them to combine instantaneously and explosively, pro- ducing water ; while a steady electric stream sent through the water annuls the affinity of its elements and sets them free again. Other causes also, known and unknown, affect in va- rious ways and degrees the play of affinity; indeed, a full statement of them would involve almost the whole science of chemistry. The changes in the properties of substances pro- duced by affinity are numberless and surpris- ing. When solid charcoal and sulphur com- bine, the compound formed is colorless as water, and highly volatile. If yellow sulphur and bluish white quicksilver be heated together, they form the bright red vermilion. Waxy phosphorus and colorless invisible oxygen unite to form a white body resembling sno'w. Ni- trogen and oxygen are tasteless, separate or mixed ; yet one of their compounds, laughing gas, is sweet, and another, nitric acid, in- tensely sour; they are both transparent and invisible, yet they form a cherry-red compound gas. Charcoal and hydrogen are odorless; nevertheless, many of our choicest perfumes, such as oils of roses and bergamot, as well as the less agreeable spirits of turpentine and il- luminating gas, contain only these elements. The mild and scentless nitrogen and hydrogen give rise to one of the most odorous and pun- gent compounds, ammonia; while suffocating and poisonous chlorine, united to a bright metal, sodium, yields common salt. Charcoal, hydro- gen, and nitrogen, which singly or mixed are not injurious to life, yet combine to form the terrible poison prussic acid; while charcoal, hydrogen, and oxygen, variously united, pro- duce sweet sugar, poisonous oxalic acid, and intoxicating alcohol. The strength of affinity among different elements is various. Thus the chemical energies of sulphuric acid are supe- rior to those of carbonic acid ; if the former be united to carbonate of lime, it takes the lime away from the carbonic acid that is, produces decomposition and a new compound. It has been attempted to establish a scale of affinities among various chemical substances to form the basis of an order of decomposition; but af- finity is disturbed and overcome by so many circumstances that such tables are of but little value. For the laws of affinity or chemi- cal combination, see ATOMIC THEORY. AFFIRMATION, a mode of solemn verification permitted by the law, in the place of an oath, to persons who are unwilling from conscien- tious motives to be sworn. This departure from the usual rule of exacting an oath was first introduced into the English law in favor of Quakers ; but by the present law there, and ever since 17 and 18 Victoria, ch. 125 (1854), any person called as a witness or desiring tt make an affidavit or deposition, who will solemnly declare that the taking of an oath is, according to his religious belief, unlawful, may affirm or declare to the truth of his statement ; and the statute requires that the officer taking the affirmation shall recite in his certificate that the affirmant declared that an oath was unlawful according to his religious belief. By the statute of 24 and 25 Victoria, ch. 66 (1861), all persons refusing to be sworn in criminal proceedings may make their solemn affirmation instead. In the United States an affirmation, even without the suggestion of any reason for preferring it, is" probably everywhere received in place of an oath. The legal effect of both is the same, and perjury is committed by affirming as well as by swearing falsely, wilfully, and corruptly. AFFRE, Denis Angoste, archbishop of Paris, born at St. Rome-de-Tarn, Sept. 27, 1793, died in Paris, June 27, 1848. He was educated in the seminary of St. Sulpice, and was made teacher of philosophy in that of Nantes before he had attained the age required for the priest- hood. After his ordination he was attached successively to the seminary of St. Sulpice and to the foundling hospital, and subsequently as grand vicar assisted the bishops of Lucon and Amiens. In 1834 he was attached to the diocese of Paris as canon and honorary vicar general. In 1839 he was appointed coadjutor to the bishop of Strasburg, but never took possession of this office ; for the archbishop's see of Paris having become vacant, he was appointed to it, and consecrated Aug. 6, 1840. In this office he distinguished himself by zeal for ecclesiastical education, and for the allevia- tion of poverty and misfortune. While the insurrection of June, 1848, was raging in the streets of Paris, he determined to make a per- sonal attempt to stop bloodshed. On the 25th he called upon Gen. Cavaignac, and, although warned by him of the great danger of his undertaking, repaired to the faubourg St. Antoine, the stronghold of the insurgents. On his appearance between the two hostile parties at the place de la Bastille, the firing was sus- pended, and he calmly and steadily proceeded toward the barricades without any protection except the gold cross on his breast and a green branch carried before him, in token of peace, by a young attendant. He was admitted be- hind the barricades, and had just begun to address the insurgents, when the report of a musket was immediately followed by a renewal of hostilities, and in the confusion the arch- bishop fell, shot by some unknown hand, and was transported to the hospital of the Quime- Vingts. He expired two days later, a martyr of charity, as was proclaimed by the national
