mutual chemical affinity of the reacting sub-
stances. Thiis, when common salt (sodium
chloride) is acted on by sulphuric acid, the latter
takes up the sodium of the former and hydro-
chloric acid is set free. According to Berginan's
teaching, the cause of tliis phenomenon lies in the
fact that sodium lias a stronger affinity for sul-
phuric than for hydrochloric acid. Berthollet,
however, advanced the view that besides chemical
affinity, there is another important factor upon
which the course of a chemical reaction depends:
viz. the relative masses of the reacting sub-
stances and of the pro<lucts of the reaction. If
hydrochloric acid, which is a gas, was not allowed
to escape during the reaction and a certain
mass of it would remain in the reacting mixture,
then only part of it could be driven out of
combination with sodium, so that when the re-
action would reach the state of equilibrium, the
mixtuie would contain, on the one hand, both
sulphuric and hydrochloric acids in the free
state, and, on the other hand, both the sulphate
and the chloride of sodium. The development
and application of Berthollet's idea form one of
the most important chapters of theoretical cliem-
istry and have thrown much light on chemical
combination. Berthollefs principal work, Essai
de statique chimique, in two volumes, appeared
in Paris in 1803. Consult: Cuvier, Eloge de
Claude Louis Berthollet (Paris, 1826) ; and Mul-
ler, Berthollet's Leben (Erlangen, 1828).
BERTHOUD, bfir'toU', Samuel Henri (1804- 1891). A French author. He was born at Cam- brai, where he edited the journal published by his father, entitled La Gazette de Cambrai. After- wards he removed to Paris, where he collaborated on Le Monde and on the Revue des Deux Mondes. He contributed to La Patrie a number of essays on natural science, under the pseudonym of Ham, which were subsequently collected in book form under the titles Faiitaisies scieiitifiques (4 se- ries, 1861) and Petites cJironiques de la scienee (1867-71). He published, several historical works, such as Chroniques et traditions siirnatu- relies de la Flandre (1831-34), a number of nov- els and many entertaining books for children, such as La France hislorique, industrielle et pittoresque (183.5-47) and Uistoir/es pour les petits et pour les grands enfants ( 1863) .
BERTI, ber'te, Domenico (1820-97). An Italian author and legislator, born at Cumiana, Province of Turin. He became professor of ethics in the University of Turin in 1849. From 1870 to 1877 he was professor of philosojihy in the University of Pome. He was Minister of Education in the La ilarmora (1866) and Rica- soli (1867) Cabinets, and Mini.ster of Commerce from 1881 until 1884. He was a Deputy almost continuously after 1849. He wrote numerous pedagogical' and political essays, and, in addi- tion, published Jl conte di Carour avante il 18.'iS (1887) ; Diario inedito con note autobioprafiche di Cavour; and numerous writings on Pico delta Mirandola, (liordnno Bruno (1898); Copernico (1876): (lalilci (1878); Cesare Alperi (1877); G. Valdes (1878) ; and others. He also founded the papers Rirista Ilaliana. Lc Alpi, and Ij'Isti- tutorc.
BERTILLON (har'te'voN') SYSTEM. The name applied to a metliod of identifying crimi- nals. Until very recently only general descrip- tions and photographs were employed, the re- sult being that by slight disguises the appear- ance was so changed that criminals frequently es- caped detection.
In March, 1879, Dr. Alphonse Bertillon, of Paris, invented and in 1885 published a plan for securing absolute identification. Three sorts of 'sigualements' (descriptions) are employed: A. Anthropometrical, based upon: (1) The almost absolute immutability of the human frame after the twentieth j-ear of age; (2) the extreme di- versity of dimensions which the human skeleton presents when compared in dill'erent subjects; (3) the facility and precision with which certain dimensions of the skeleton may be measured. B. Descriptive ; a general description. C. Peculiar marks, scars, deformities, etc. Of these marks an exact measurement is taken and their loca- tion accurately noted. The color of the eyes is important, as this cannot be changed. Two pho- tographs, one of the full face, the other of the profile, are taken by a camera screwed to the floor, and from a chair likewise fastened so that the relative proportion of height and size are ex- actly preserved in all pictures. The main reli- ance, however, is placed on the anthropometrical signalments, as these are never identical for two persons. The measurements taken are (the metric system is always used) :
Bodv Height (person standing). Reach (outstretched arms — finger-tips to finger-tips) . Trunk (height sitting). TT 1 / Length and width. Length and width of right ear. Length of left foot, left middle finger, l^iniDs^ left little finger, left forearm.
The measurements, with the other descriptions and the photographs, are put on cards of uni- form size. These cards are classified, first ac- cording to sex. The cards are then distributed in three tiers of drawers, each tier made up of three drawers, according to the length of the head. The upper tier contains head lengths of 187 millimeters and less; the middle, those between 187 millimeters and 194 millimeters: the third, all above 194 millimeters. Ninety thousand cards would thus be roughly divided , into tiers of 30,000 each. Each of these groups is subdivided according as the width of the head is narrow, medium, or broad, each division hav- ing about 10,000 cards. A further division, ac- cording as the length of the left middle finger is small, medium, or large, will reduce them to groups of 3300 cards. Further analysis soon lowers the numlier of cards to something like 12 in each group. Thus to locate any card re- quires but a moment's efl'ort.
The Bertillon system was introduced into the United States in 1887 by Major R. W. JIc- Claughry. It met with a favorable reception and is rapidly being adopted in the larger jienal in- stitutions.
Such a system of absolute identification is a "necessary adjunct to the scientific administra- tion of criminal law." It has a deterrent effect upon criminals, who know that if they are caught no disguise can conceal their identity. It enables the officers to distinguish the new from the old oft'ender. It makes impossible the mistaking of an innocent person for some criminal to whom he bears a superficial resemblance. With the in- creased sentences for repeated offenses, this possi-
