128 



NATURE 



[April i, 1920 



have been used; and lastly, that the principal 

 author who mentions it— Guy de Chauliac— gives 

 no indication that it was a method that he either 

 approved or had ever employed. 



This is the general character of the book. 

 History written on these lines has ceased to be 

 scientific, and, however attractive, learned, or 

 entertaining, cannot be regarded as a serious at- 

 tenipt to interpret the past in the light of present 

 knowledge. Charles Singer. 



Ancient Camps in Gloucestershire. 



The Ancient Entrenchments and Camps of 

 Gloucestershire. By Edward J. Burrow, i 

 Pp. 176. (Cheltenham and London : Ed. J. ! 

 Burrow and Co., Ltd., n.d.) Price 21s. net. j 



AN observer who casts his eye over one of the i 

 most delightful landscapes in England, the 

 view of the Severn Valley as seen from the escarp- 

 ment of the Gotswolds, with the Malvern range i 

 and the Welsh mountains in the far distance, must 1 

 have noticed the numerous ancient fortifications < 

 which stud the Cotswolrf glacis. Wave after wave 

 of conquest and armed occupation has broken 

 against this hill rampart. Goidel and Celt, British, 

 Roman, Saxon, Dane, and Norman in succession 

 occupied these uplands, and gradually brought the 

 rich valley lands under the plough. The camps 

 remain as evidence of these struggles in the distant 

 past, down to the time when Cromwell drew his 

 entrenchments on Churchdown Hill at the siege 

 of Gloucester. 



We have little trustworthy history beyond Neo- 

 lithic flint implements and similar remains of the 

 builders of these fortifications, until some of them, 

 like Chipping Norton and Landsdown, near Bath, 

 were occupied by the Romans probably before they 

 reached the stage of constructing fortified cities on 

 the model of the camps of their legionaries, like 

 Glevum (Gloucester) or Corinium (Cirencester). 

 When Christianity replaced paganism, some of 

 these camps, like those at Churchdown and Old- 

 bury, became the sites of Christian churches. 



The oldest form of camp seems to have been 

 the hill-fortress, generally consisting of a strong 

 bank and ditch, either cutting off a projecting 

 headland from the downs, or marking off an area 

 with an irregular oval line of entrenchments, the 

 two ends resting on the escarpment of the hill. 

 But the more developed types are infinitely varied, 

 often showing considerable strategical skill in the 

 selection of the site, the alignment of the ramparts, 

 and the provision of a water supply. Others, 

 , again, were not designed for permanent occupa- 

 tion, being merely temporary shelters for human 

 beings, cattle, and grain in the event of a sudden 

 NO. 2631, VOL. 105] 



raid by the Silures or other formidable tribes of • 

 the West Country. 



Much information regarding these camps was 

 collected' by the late Mr. G. B. Witts in his 

 "Archaeological Handbook of Gloucestershire," 

 by the local historians, and in the Proceedings of 

 the local societies. Mr. Burrow, though not a 

 trained antiquary, has done useful work in com- 

 piling this monograph. After an introduction deal- 

 ing briefly with the ethnographical and historical 

 aspects of the question, he describes in alpha- 

 betical order more than a hundred encampments, 

 and he is careful to give references to the authori- 

 ties on which his notices have been based. A dis- 

 tinguishing feature of the book is the series of 

 excellent illustrations from sketches by the author 

 of all the encampments described. The format 

 of the book is creditable to the local printers, and 

 the monograph, as a whole, is a good example of 

 careful field work and artistic taste. 



Principles of Glass-making. 



Glass Manufacture. By Dr. Walter Rosenhain, 

 Second edition, largely re-written. Pp. xv + 258- 

 (London: Constable and Co., Ltd., 1919.) 

 Price 125. 6d. net. 



THIS volume is very welcome, because there 

 are so few English books on glass-making. 

 It brings the author's 1908 edition up to date. 

 It is easy to read and interesting throughout. The 

 preface states that the book is intended for those 

 who are users of glass, and makes no claim to 

 be an adequate guide or help to glass manufac- 

 turers ; this makes the book rather a disappoint- 

 ment to a glass-maker, who, from the title, would 

 expect more explicit information. 



The author invariably keeps to general prin- 

 ciples, and does not give any practical particulars^ 

 and in some cases just stops when there is no 

 need to do so. For example, on p. 17 he states 

 that results serve to show that chemical composi- 

 tion has a profound influence on the mechanical 

 strength of glass, and on p. 18 that the modulus 

 of elasticity was largely dependent on the chemical 

 composition of the glass — then why not say in 

 general terms in which direction the mechanical 

 strength and the modulus of elasticity vary with 

 the chemical composition? On p. 36 the pure 

 sands are stated to contain o'2 to 0*3 per cent, of 

 iron ; this is evidently an error, and should read 

 o'02 to 003 per cent. 



The chapter on "Raw Materials " is instructive,, 

 but the author overlooks the fact that dolomite is 

 by far the cheapest form in which to introduce 

 magnesia into common types of glass. The remarks 

 on dimension and height of tank furnace crowns 



