58 



CELTS 



CEMENTS 



invasions ; the one is represented by the Celts 

 whose position, geographically speaking, is the 

 farthest from the home of the Aryans. These 

 would be the Celticans of Gaul and Spain, as 

 compared with the Gallic tribes to the east of 

 them towards the Rhine and the Alps ; the same 

 relative position is also taken up by the Goidelic 

 Celts of the British Islands, occupying, as we find 

 them doing, the Isle of Man, Ireland, and, the 

 Scotch Highlands and Islands. The other, here 

 represented by the Brythons, must have come 

 later and driven out the Goidels, or subdued them, 

 in the rest of this island. This may be supposed, 

 also, to have been the case on the Continent, so 

 that we have to regard the later comers, the Galli, 

 as invaders and conquerors forming another Celtic 

 population. In the eastern portions of Gaul they 

 may have formed the bulk of the population, but 

 in the rest of that country they probably only 

 constituted a ruling class of comparatively small 

 importance in point of numbers. Such a state of 

 things would adequately explain the great dearth 

 of linguistic remains belonging to the older and 

 subjugated people. Roman authors and other 

 strangers would naturally speak most of the ruling 

 classes, and information about the others must 

 reach strangers through the medium of the Gallic 

 rulers and their language, at anyrate, so far as 

 concerns the time before Latin became the official 

 tongue of all Gaul. A somewhat similar conclusion 

 has been arrived at by studying the burials and 

 megalithic monuments of France and the neigh- 

 bouring lands to the east of it. In Central and 

 Western France menhirs, dolmens, and cromlechs 

 prevail, while the eastern side of France shows 

 the prevalence of mounds and barrows, which are 

 here and there found penetrating into the other 

 domain, giving us a sort of rude sketch, as it were, 

 of an invasion advancing irregularly towards the 

 west. See M. Bertrands Archeologie Celtique. et 

 Gauloise ; also K. von Becker's Versuch einer 

 Losvng der Celtenfrage (1883), pp. 114-119. 



For reasons already indicated, the question of 

 Celtic ethnology is a very difficult one, but it is 

 considerably more difficult than would appear from 

 what has here been mentioned ; for besides two 

 Celtic sets of invaders, there are also to be taken 

 into account the non- Aryan races that previously 

 occupied the countries to which the Celts came. 

 These pre-Celtic populations probably survived in 

 considerable numbers, and one of the effects of a 

 second Celtic invasion may be supposed to have 

 been to force the earlier Celtic settlers to amalga- 

 mate with the ancient inhabitants, and to make 

 common cause with them against the later Aryan 

 hordes. So it may be expected that the language 

 of the Goidelic Celts will prove to have absorbed 

 a larger non-Aryan element than that of the 

 Brythons. Similarly, one might take for granted 

 that the physical type of the people speaking the 

 Goidelic dialects should prove less purely Aryan ; 

 but this feature is obscured by the fact of the 

 counter-invasions which Wales and other western 

 portions of Britain have undergone in historical 

 times at the hands of Ireland. Lastly, it is right 

 to add that in so far as the people, whose language 

 is or has been Celtic, are Aryans, one might expect 

 the type to be that of tall men, with more or less 

 light hair and blue eyes ; on the other hand, the 

 smaller men, with dark hair and black eyes, which 

 it was the fashion till lately to regard as the 

 genuine and typical Celts, are probably not to be 

 regarded as Celts at all, but as Ivernians or 

 representatives of the pre-Celtic and non-Aryan 

 race, whose hunting-ground the soil of the British 

 Islands may be said to have been long before the 

 first Aryan set foot in them. 



The Celtic languages and literatures will be found 



under BRITTANY, CORNWALL, GAELIC, IRELAND. 

 WALES. See also ARYAN RACE AND LANGUAGES; 

 ETHNOLOGY, PHILOLOGY, DRUIDISM. 



Besides the works already mentioned, the following 

 should be consulted : Miillenhoff's Deutsche Altertums- 

 kunde (Berlin, 1887); Windisch's article 'Keltische 

 Sprachen' in the Allgemeine Encyklopcedie der Wissen- 

 schaften und Kunste, together with the reviews on the 

 same in the Revue Celtique, vol. vi. pp. 395-400; 

 Hiibner's Inscriptiones Britannia! Christiana (Berlin, 

 1876 ) ; Brambach's Corpus Inscrip. Rhenanarum ; and the 

 volumes of the Corpus Inscrip. Latino/rum, published by 

 the Berlin Academy, especially those for Britain (vii.), 

 Spain (ii.), Gallia Narbonensis (xii.), Gallia Cisalpina 

 (v.), and Illyricum (iii.). 



Cements* These may be roughly divided into 

 three classes : ( 1 ) The stone cements, including 

 Roman and Portland cements, and ordinary mortar, 

 which are used in thickish layers for uniting stone 

 and brick work, and for protective coverings to 

 buildings ; ( 2 ) substances which form binding 

 joints of much less but still appreciable thickness, 

 such as white lead, red lead, and putty; and (3) 

 cements which require to be used in extremely thin 

 coatings, such as glue, isinglass, and dissolved 

 caoutchouc. 



Ordinary Mortar is a mixture of slaked lime 

 (calcium hydroxide) and sand, made into a paste 

 with water. Generally one part of lime to three 

 or four parts of sand are used, but the proportions 

 vary according to the purity of the lime employed. 

 Very pure or fat lime, such as that made by burn- 

 ing white chalk or white marble does not make 

 so good a mortar as lime obtained from less pure 

 limestones, which are by far the most abundant. 

 The more thoroughly the ingredients are inter- 

 mixed, the more complete will be the subsequent 

 hardening of the mortar. As commonly laid in the 

 joints of brick or stone work, mortar sets suffici- 

 ently fast to allow building operations to proceed 

 from day to day with occasional longer intervals, 

 but it takes years perhaps in many cases cen- 

 turies to reach its maximum hardness. The 

 setting and subsequent slow hardening of mortar 

 are usually considered to be due, in the first in- 

 stance, simply to the loss of water, and afterwards 

 to the absorption by the lime of carbonic acid from 

 the atmosphere, the carbonate of lime thus formed 

 binding together the sand and stone. It is doubt- 

 ful, however, if this is an altogether satisfactory 

 explanation. The mortar used in many medieval 

 buildings is largely mixed with small pebbles. In 

 a number of cases this has proved to be of a more 

 durable nature than the stone used along with it. 



Puzzolana or Pozzuolana, a loosely coherent 

 volcanic sand found at Pozzuoli, near Naples, has 

 been long celebrated for its property of forming 

 a hydraulic cement when mixed with ordinary 

 lime. It is composed of silica, with a little 

 magnesia and potash or soda, alumina, lime, and 

 oxide of iron. 



Roman Cement. Certain natural mixtures of 

 lime and clay are called cement-stones. The clays 

 of some of the newer geological formations in the 

 south of England, for example, contain courses of 

 septarian nodules (see SEPT ARIA), which have been 

 in great request for making the best kinds of 

 Roman cement. They are concretions of impure 

 calcareous matter, many of them having this 

 analysis: Carbonate of lime, 66; silica, 18; alumina, 

 7 ; and protoxide of iron, 6 ; or consist of these sub- 

 stances in nearly that proportion. Cement-stones 

 are carefully calcined in kilns, and afterwards 

 ground and sifted. Good Roman cement should 

 set in about 15 minutes, and this quick-setting 

 property makes it valuable for work which requires 

 to be executed between tides and for other purposes 

 where the cement used must harden quickly. It is 

 at best of but medium strength. Some natural 



