Mar. 14, 1S72] 



NATURE 



389 



described by Herodotus ; that some of the tumuli on the 

 eastern shores of the Mediterranean are certainly " as old 

 as the thirteenth century, B.C. : that the practice of bury- 

 ing in tumuli must have existed for many centuries before 

 such tombs could have been constructed ; and that the 

 age in which they "were erected was essentially the age 

 of bronze : not only are the ornaments and furniture 

 found in the Etruscan tombs generally of that metal, but 

 the tombs at Mycena; and Orchomenos were wholly lined 

 with it ; " a fact which is the more interesting when we 

 remember that all the metallic objects found in the tumuli 

 round Stonehenge were of bronze. 



Again.let us consider the class of monuments which con- 

 sist of a free dolmen standing on a mound, and surrounded 

 by one or more stone circles. This type is very widely dis- 

 tributed. A Danish example has already been given, Fig. 

 5. Fig. 4 represents the long barrow at Kennet, near 

 Marlborough, after Dr. Thurman ; Fig. 2 is the Dolmen 

 de Bousquet in the Aveyron ; lastly. Fig. 7 is a similar 

 monument at Pullicondah, near Madras. These tumuli, 

 though differing in detail, are identical in all essential 



Fig. 8.— General Plan of Stonehenge, from Knight's "Old Englnnd." 



points. If these monuments all belong to post- Christian 

 times, they must have been erected by very different 

 races of men. Mr. Fergusson, indeed, admits that they 

 are the work of very different races ; how then does he 

 account for the remarkable similarity existing between 

 them? He denies thatthe Celts, Scandinavians, or Iberians 

 were themselves naturally " rude stone builders,'' and en- 

 deavours to remove the difficulty by an explanation which 

 is most important, because it seems to me to involve the 

 practical abandonment of the conclusion, which, as he 

 told us in the preface, is the central feature of his work. 

 This style of art, he says, " seems to have been invented 

 by some pre-Celtic people, but to have been adopted by 

 Celts, by Scandinavians, by British, and Iberian races." 



But if Europe was once occupied by a pre-Celtic, mega- 

 lithic-monument-building race, surely some of our mcga- 

 lithic monuments must be ascribable to that time and race, 

 and we come back therefore to the general opinion of 



archreologists, that our megakthic monuments belong to 

 very different periods and people, and not all to one race 

 or one epoch. 



I cannot now enter into the consideration of the dates 

 to which Mr. F'ergusson ascribes individual monuments ; 

 I doubt whether any belong to so recent a period as he 

 supposes : and can only express my surprise at the cer- 

 tainty and confidence which he feels in his own opinions — a 

 certainty sometimes, however, oddly expressed, as, for in- 

 stance, when he tells us, speaking of the crosses at Kata- 

 pur, which he considers to be Christian and contem- 

 poraneous with a group of neighbouring dolmens, ihot 

 " their juxtaposition and whole appearance render escape 

 from this conclusion apparently inevitable." 



But while I cannot accept Mr. Fergusson's peculiar 

 theories, I cannot conclude without thanking him for the 

 labour and care with which he has brought together a 

 great number of illustrations, and a vast mass of facts, 

 on this most interesting subject. In a review, one natu- 

 rally dwells on points of difference, but every one must 

 accord to Mr. Fergusson the credit which, in the follou-- 

 ing passage from his preface, he claims for himself ; 

 though I would venture to add that the unintentional 

 self criticism in the latter sentence seems to me not in- 

 applicable. "I have," he says, ''spared no pains in 

 investigating the materials placed at my disposal, and no 

 haste in forming my conclusions." His conclusions are, I 

 think, in some cases, hasty and untenable ; some seem in- 

 consistent with one another ; but no one can deny to his 

 work the merit of being a rich and trustworthy store- 

 house of facts. John Lubbock 



THE STUDY AND TEACHING OF MECHANICS 



A LECTURE on this subject, being one of the series 

 -'^ of lectures at the College of Preceptors on the 

 Teaching of Physical Science, was given by Prof. \V. C-. 

 Adams, of which the following is the substance : — 



Mechanics treats of the laws of equilibrium and cf 

 motion of bodies, and in its widest sense, as the science 

 of energy, must include all branches of Physics, for the 

 solid, liquid, and gaseous states of bodies are determined 

 by the more or less free motion of their molecules, and 

 heat, light, electricity and magnetism are all different 

 forms of motion. The study of the laws of equilibrium 

 and of visible motion is impoitant, both for their practical 

 applications and because on therrr ai-e founded the prin- 

 ciples of thermo- and electro- dynamics. Before entering 

 on a study of mechanics, students should have a know- 

 ledge of algebra and geometry, and on account of the 

 importance of accurate measurement, the elements of 

 trigonometry should also be studied. By a proper 

 method of teaching geometry, boys can be taught to 

 think, and the exact definitions and proofs of Euclid's 

 Elements are better fitted to train the judgment and the 

 reasoning powers than any less exact system of geometry. 

 The way to teach geometry (and the same remark applies 

 to mechanics) is not to expect boys to get up their Euclid 

 from a book, and to say it off by the aid of a book cf 

 figures (a system which has been practised in many 

 schools), but to explain the meaning of and illustrate 

 every proposition, so that boys may under.'^tand it. The 

 true method of teaching mechanics is illustrated by the 

 way in which Galileo established the first piinciplcs 

 of dynamics, and placed them before his pupils. Due 

 weight should be given both to experimental and to 

 rational mechanics, and the best way of bringing the sub- 

 ject before students is to have parallel but distinct 

 courses of experimental and theoretical lectures attended 

 by students at the same time. The practical applications 

 of the subject are import.Tnt, and some of them of great 

 simplicity. The "Triangle of Forces" may be employed 

 to build up diagrams to represent the thrusts on a jointeij 



