tery increase with its chemical action, a fact which had been denied or doubted by other experimenters.
In 1844 Gassiot showed by experimenting with delicate micrometer apparatus (Philosophical Magazine for October) that Grove's arguments against the contact theory of electricity were correct. In conducting a series of experiments upon the decomposition of water by electricity, Gassiot showed that when the liquid was under a pressure of 447 atmospheres it offered no extra resistance to the passage of the electric current. In 1852 Grove discovered the dark bands, striæ, or stratification, of the electric discharge; and to the study of this phenomenon he devoted much time and money. He showed that these striæ accompany all electric discharges in vacuum tubes, and that they occur equally well when, as is the case when the discharge takes place in the Torricellian vacuum of a barometer, no contact-breaker is employed. His researches on this matter formed the subject of the Bakerian lecture before the Royal Society in 1858. Gassiot further proved that when vacuum tubes are exhausted of their gases beyond a certain limit, the electric discharge will not pass at all. Gassiot died in the Isle of Wight, 15 Aug. 1877.
[Journ. of Chemical Soc. for 1878, xxxiii. 227; Nature for September 1877, pp. 388, 399; Royal Soc. Cat. of Scientific Papers; information communicated by relatives.]
GAST, LUCE de (fl. 1199?), knight and lord of the castle of Gast, near Salisbury, is mentioned in preambles to many manuscripts of the great prose romance of Tristan. It is stated that he wondered that no one had translated into French the Latin book containing the history of the Saint Graal, and at length decided to do so himself, although in language he belonged rather to England, where he was born (MSS. 6768 and 6771 in Bibliothèque, and Add. MS. 23929 in Brit. Mus.) Only the first part of Tristan is ascribed to Gast, the second being assigned to Hélie de Borron. It is at least questionable whether either writer ever existed. Gast professes, and in this Hélie de Borron supports him, to have been the first to make use of the records of the Round Table, and to have chosen Tristan for his hero, as being the most puissant knight that was ever in Britain before King Arthur, or afterwards, save only for Lancelot and Galahad. But whereas the Tristan is full of allusions to the Saint Graal and to Lancelot, these romances never mention Tristan as an Arthurian hero; the romance of Tristan was therefore probably the later composition. Nor is there any proof of the existence of a Latin original. In all probability the prose romance of Tristan was founded on the lost poem of Chrétien de Troyes, which must have been written about 1160. It is also noticeable that in the Quest of the Saint Graal, the Records (of the Quest, at all events) are said to be kept ‘en l'aumoire de Salebères.’ It looks as if the whole story of the knight, his castle, and the Latin book were an invention intended to give an appearance of authority to the romance. The Tristan was first printed at Rouen in 1489, and afterwards at Paris by Antoine Verard in two editions without date; again at Paris in 1514, 1520, 1533 (Brunet, Manuel du Libraire, vol. v. col. 955). These printed copies follow the version as it was rearranged by writers of the fourteenth and fifteenth centuries, and differ greatly from the original work. One manuscript (Bibliothèque 6976) ascribes to Gast the ‘Roman de Guyron le Courtois,’ which is more commonly assigned to Hélie de Borron. The name is variously spelt Gast, Galt, Gant, or Gay. It has been endeavoured to identify it with one of two castles called Gât in Normandy, but all the manuscripts clearly describe Gast as ‘voisin prochain de Salebères.’
[Paulin Paris' Manuscrits François de la Bibliothèque du Roi, vols. i. and iii.; Ward's Cat. of Romances in the Brit. Mus. vol. i.; Gaston Paris' Littérature Française au Moyen Age. The writer has also to thank Mr. Ward for some additional information.]
GASTINEAU, HENRY (1791–1876), painter in water-colours, was a student at the Royal Academy. He commenced his artistic career as an engraver, but soon relinquished that branch of art for painting, commencing in oil, but eventually settling down exclusively to water-colour. He joined the Society of Painters in Water-colours in 1818, and then exhibited for the first time. In 1821 he was elected an associate, and in 1823 a full member. He continued to exhibit for fifty-eight years continuously, during which he worked unweariedly at his profession, and with unflagging powers. He exhibited eleven pictures when eighty-five years of age. As a contemporary of David Cox, Copley Fielding, G. Cattermole, S. Prout, and others, he adhered throughout his life to the old style and manner of water-colour painting. Though he cannot be said to have attained the first rank in his profession, he showed great taste and discrimination in the treatment of his subjects, and, if these indicated little variation, he exhibited so refined a feeling for nature that they are highly valued by artists and others as ex-
