August 3, 1883.] 



SCIENCE. 



139 



For purposos of coinparisoii, the editor has 

 given an engraving of an enamelled bronze cup, 

 of similar shape and method of manufaeture, 

 which was found at llarwood, in Northumber- 

 land, and is now in the British museum. He 

 al.so describes a facsimile cast of a beautiful ves- 

 sel, known as the ' Hartlow vase,' the original 

 of which was nearly mined in a fire which took 

 place in the mansion of Loni Mayuard, b^- 

 whom it was discovered in \h:V2, during excava- 

 tions made in a series of remarkable flat-topped 

 tumuli situated atBartlow, in Kssex. A plate 

 showing it in all its pristine bcaut\' may be found 

 in ArdiKeologiii, vol. 26, pi. 35. It is now in 

 the British museum, where can also be seen a 

 similar vase, discovere<l at Ambleteuse, near 

 Boulogne. Still another of the same charac- 

 ter, found in the western part of France, is 

 preserved at Angouleme. Finally in the Afe- 

 moires de la societe desantiquairesdu nord,n.s.. 

 1868, there is represented an exceedingly beau- 

 tiful specimen of an enamelled bronze cup of 

 the same pattern, discovered in 1867 in a peat- 

 moss at Maltboeck, in the southern part of 

 the peninsula of Jutland, in Denmark. 



Beside these vases, enamelled fibulae and 

 horse-trappings have frequenth" been found in 

 ancient graves, especially in England. Pro- 

 fessor Boyd Dawkins, in his Cave-hunting, also 

 gives a plate representing several brooches of 

 this kind, which were discovered during the 

 explorations of the Victoria cave, in Settle, 

 Yorkshire. This was so named on account of 

 its discover^" upon the coronation day of Queen 

 Victoria, in 18;59 ; and it is especially interest- 

 ing as having been a place of refuge of the mis- 

 erable British fugitives who fled before the 

 sword of the ' conquering Engle.' 



The art of enamelling was known to the 

 ancient Egyptians, the Etruscans, and the 

 Greeks ; but the last had ceased to make use 

 of it at least two hundred years B.C. By the 

 Romans it was never practised at all ; and it is 

 not alluded to by Pliny in his encyclopedic 



■ Natural history.' The only reference to it to 

 be found in any ancient author occurs in the 

 Imagines of Philostratus the elder (lib. i., im. 

 27). In a description of a picture of a boar- 

 hunt, after enumerating the diflferent colors of 

 the horses ridden by the youthful huntsmen, 

 and saying that the hits were of silver and the 

 housings enriched with gold and various colors, 

 he adds, "They say that the barbarians, who 

 dwell near the ocean, pour these colors upon 

 heated brass, and that they adhere, and become 

 like stone, and preserve the designs made by 

 them." Now, I'hilostratus was a Greek rhet- 

 orician, called from Athens, in the beginning 

 of llie third century, to the court of^ Julia 

 Domna, wife of tiie emperor Septimins Sev- 

 erus. As this emperor passed considerable 

 time in Britain, where he built, or at an}- rate 

 repaired, the wall that goes by his name, and 

 died at York, it is by no means improbable 

 that Philostratus gained his knowledge of the 

 processes of enamelling from accounts brought 

 to the court from that region. To the English 

 antiquaries it seems to be established, by the 

 number and the beauty of such objects that 

 have l)ecn discovered in their own country, that 

 this was the principal seat of its manufacture ; 

 and Mr. John R. Green does not hesitate to 

 call the ' party-colored enamel the peculiar 

 workmanship of Celtic Britain.' But from 

 the fact that the late Abbe Cochet has found 

 precisely similar enamelled objects in his ex- 

 plorations of ancient cemeteries in Normandy, 

 and from the discovery of cups of the same 

 kind upon the soil of France, the anti(|uaries 

 of that nation maintain that their own countrj-- 

 men were ' the barbarians that dwelt near the 

 ocean.' Non nostrum tantas componere lites ; 

 but certainly objects of this character ought 

 never to be styled • Roman.' 



We wish that we had more space at our dis- 

 posal to direct attention to the many other 

 beautiful objects of antiquity to be found in 

 this fine collection. IIenuv \V. IIaynes. 



WEEKLY SUMMARY OF THE PROGRESS OF SCIENCE. 



MATHEMATICS. 

 Lineeir differential equations. — M. G. Floquet, 

 in a paper entitled " Sur Us equations (Uffirentielles 

 lineaires a coefficients pi'riodique," has made an in- 

 teresting and scpmiiigly important addition to the 

 literature of periodic (unctions. He considers a ho- 

 mogeneous linear differential equation of the fonn 



Ply), 



,+. . . + pmy-*>. 



the coefficients being uniform functions having all 

 the same period, u, and the general integral being sup- 

 posed uniform. If the variable be changed by the 

 substitution 



the result is a linear transformation of P, in which 

 the coefficients are uniform functions of i. From the 

 known expression for Its integrals in the region of a 



