332 



NATURE 



[February i, 1500 



the citizens of Norwich, dated June 29, 1286. That the culture 

 and preparation of woad was practically the same in the time of 

 Rueliius (1536), Crolachius (1575), Wedelius (1675), and Ray 

 (1686) as it is now their writings show. It is probable some 

 very simple process was used by the dyers in these olden times, 

 as simple as that by which the blue colour can be obtained from 

 the fresh plant— at any rate, less complicated than the woad- 

 vat Helliot describes in 1750 for dyeing with woad and indigo, 

 and which is given, with variations, in encyclopredias down to 

 the present time. Charles B. Plow right. 



CONTACT ELECTRICITY. 

 A T the meeting of the Physical Society, a few weeks ago, 

 when the subject of Contact Electricity was under dis- 

 cussion, the President was asked by his friendly opponents to 

 commit himself to a definite interpretation of the fundamental 

 equation, and to a precise statement as to what quantity he re- 

 cognised as "contact potential difference." Prof Lodge did 

 not then comply with the request, but he promised to address 

 the Society upon " Contact Electricity " at their annual general 

 meeting on February 9. It is rather a matter for regret 

 that this ancient feud is so near to amicable settlement. The 

 controversy has held its own for a little more than a century, 

 and throughout that time it has acted as a never-failing stimulus 

 to research in the laboratory. Physicists are now retracing the 

 steps of their arguments, revising their definitions, amending 

 their phrases, and trying hard to understand one another's 

 parlance. No scientific dispute can outlive such precautions. 



The case fcr both sides has frequently been stated. Perhaps 

 the best account consistent with brevity is that given in Prof. 

 A. Gray's " Magnetism and Electricity," Chap. xii. This, in 

 common with all modern summaries of the subject, is admittedly 

 -derived from Prof. Lodge's British Association Report of 1884. 

 Those who desire to bring themselves into closer acquaintance 

 with the latest developments of the argument should read the 

 ■article on " Contact Electricity," by Mr. W. A. Price, 

 in the Electrical Review of December 29, 1899. Mr. Price 

 seeks to locate the dispute to the meaning of words, and chiefly 

 to the word "potential." He explains that "potential" is 

 essentially a property of a position in space, and that it implies 

 neither the existence nor the absence of matter near or at a 

 point of which potential is predicated. The expression 

 " potential at a point " has per se no ambiguity. But when 

 measurements of the potential at a point are required, the 

 methods employed, from their indirect character, nece.ssitate 

 certain assumptions ; and the quantity is no longer free from 

 ambiguity. Potential is generally measured indirectly, as the 

 result of an investigation of the electrical force in the neighbour- 

 hood of the given point. The value, so obtained, involves 

 therefore the physical qualities of the fluid medium or media 

 associated with the point, and these have no place in the primary 

 definition of potential. There is, in fact, no experimental 

 foundation for the statement that within a conducting body, not 

 conveying electricity, potential has the same value at all points. 

 Hence no conclusions can properly be drawn until physicists 

 agree amongst themselves as to their cardinal definitions ; and 

 when this is accomplished, the controversy will have ceased. 



A GRIC UL TURA L ED UCA TION. 



W" 



'E are slowly realising that success in farming depends quite 

 much upon scientific knowledge as upon practical 

 framing. In other countries this fact has been fully appreciated 

 for many years, and elaborate provision for the interests of agri- 

 culttjre forms a prominent feature of their educational systems. 

 Similar provision has become a necessity for England, if we are 

 to compete with them upon anything like equal terms. In 

 furtherance of this object the Agricultural Education Committee, 

 of which some of the most eminent men of science and agricultur- 

 ists of the day are members, has recently issued certain definite 

 proposals. Foremost amongst these is a recommendation that all 

 the educational work of the Board of Agriculture should, like 

 that of the Science and Art Department, be transferred to the 

 new Board of Education. If the confusion, overlapping and 

 wasteful expenditure of public money, which have resulted from 

 the multiplication of central authorities, are to be avoided, it is 

 essential that one authority alone should be responsible for the 



NO. I 579. VOL. 61] 



of this authority, aided by inspectors thoroughly familiar with 

 the needs of the agricultural classes, and with the conditions of 

 rural life, to secure an adequate provision of the various forms 

 and degrees of instruction required by all those who are in any 

 way concerned with the cultivation of the soil. 



Such instruction must commence with the elementary school, 

 for that is the foundation upon which the whole superstructure 

 has to be built, and the Committee emphasises the importance of 

 differentiating the curriculum of the rural from that of the urban 

 school. This change is not advocated under the impression that 

 it will stem the tide of migration from the country districts. A 

 variety of social and economic causes combine to drive men from 

 the villages into the towns. At the same time, on the principle 

 that "as a twig is bent, so will the tree incline," it is hoped 

 that if children were familiarised from their earliest years 

 with the simple facts of nature, and encouraged to take an in- 

 telligent interest in them, a love of the country might be 

 awakened, and the desire to remain in it certainly be strength- 

 ened. No suggestion of teaching agriculture or .science as 

 such is put forward : years ago, Prof. Huxley pointed out the 

 futility of attempting to teach either one or the other in an 

 elementary school. A rural curriculum should include ele- 

 mentary science lessons upon the life, growth and structure 

 of plants, the habits of birds, animals and insects, the nature 

 of the soil, and air and water, and the utility of the simpler 

 methods" of cultivation. These lessons should be illustrated 

 by experiments, and be accompanied by practical work, 

 appropriate to the agricultural character of the locality, done 

 by the pupils themselves in gardens or on plots of ground 

 attached to the school. They should be supplemented 

 further by occasional visits to well-managed farms, and valuable 

 assistance might be given by circulating amongst the teachers 

 and pupils leaflets, similar to the admirable " Nature-Study 

 Leaflets" issued by the agricultural college in Cornell Uni- 

 versity. In like manner girls should receive elementary in- 

 struction in cooking, domestic economy and hygiene. In either 

 case the child will be developing those faculties, and forming 

 those habits, which enable a boy to become a skilled labourer 

 or a successful farmer, and a girl to become a competent servant 

 or a capable housewife. To meet the difficulties of small 

 schools, several parishes must coirtbine to engage the services of 

 a peripatetic teacher. There can be no doubt that in the 

 grouping of villages and schools for educational purposes the 

 solution of many of the problems of rural education will 

 ultimately be found to lie. 



As yet it is not easy to find properly qualified teachers, but 

 the Committee suggests various ways in which they may be 

 trained. At the normal colleges in France theoretical and 

 practical instruction in agriculture is provided for the students 

 by the departmental professors, and there does not appear 

 to be any reason why students at some of the training colleges 

 in England should not be similarly taught by the lecturers of the 

 County Councils. It should be remembered that the rural school 

 does not require an agricultural expert ; such a teacher would 

 inevitably give undue prominence to one aspect of elementary 

 education, and it might reasonably be objected that an attempt 

 was being inade to capture the .schools in the interest of one 

 section of ihe community only. The rural teacher should have 

 a general knowledge of the principles underlying the science of 

 agriculture, and some practical knowledge of agricultural 

 operations. Men so qualified will be rapidly forthcoming as 

 the demand for them becomes more general. In the meantime 

 existing teachers should be assisted to acquire the necessar)- 

 experience by County Council lectures, practical demonstrations 

 on farms and in gardens, and courses of instruction at agri- 

 cultural colleges ; special facilities by means of scholarships or 

 bursaries should be offered to rural pupil teachers for a course 

 of some duration at any institution where theoretical and 

 practical instruction might be had. 



It is necessary to insist upon the importance of the lower 

 branches of agricultural education in view of the small attention 

 which has hitherto been paid to them. The hope of the future 

 lies in our having a constant relay of pupils from the elementary 

 schools fitted to attend and profit by the more advanced classes 

 and colleges. For the majority of rural children evening 

 continuation schools afford the only opportunity for further 

 instruction, and the Committee recommends that it should be 

 made part of the duty of every county organisation (outside 

 London and the county boroughs) recognised under Clause VII. 



