760 



NATURE 



[August 12, 1920 



in^« of forest crops, and (2) that dealing with the 

 utilisation of timber and other forest products. Each 

 of these two main branches can be considered from 

 two points of view, namely, the general and the local, 

 the former being concerned with the principles and 

 methods governing research work, and the latter with 

 the application of principles to a limited range of 

 conditions. General research may, consequently, be 

 conducted, at one centre for very wide areas, while 

 local research must be conducted on the spot. 

 Although the two main branches of research are 

 intimately connected, from their nature they cannot 

 always be conducted at the same institution ; it is, 

 however, impossible to lay down any hard-and-fast 

 rule in the matter, and, provided adequate co-ordina- 

 tion is secured, there is no reason why the two 

 branches of research may not be conducted success- 

 fully either together or apart, as circumstances may 

 dictate. Most of the research problems of outstanding 

 importance fall under the head of sylvicultural, statis- 

 tical (that is, the collection and collation of data 

 dealing with rate of growth and production), or 

 technological. The conference recorded the opinion 

 that in no part of the Empire is sufficient attention 

 paid to the investigation of sylvicultural and statis- 

 tical problems, considering their great importance in 

 connection with the future maintenance and economic 

 working of the forests ; accordingly it recommended 

 tbfit each part of the Empire should include- in its 

 forest service at least one research officer, and that 

 adequate funds should be placed at his disposal to 

 ensure progress in these branches of research. 



Specific proposals were made in respect of forest 

 research work in different parts of the Empire, and 

 it may be of interest to note the views of the con- 

 ference in regard to the organisation of work in the 

 United Kingdom. It was held that requirements 

 would be met by the establishment of (i) a research 

 institute to deal with problems connected with the 

 growing of forest crops, and (2) a research organisa- 

 tion which should include a central institute to deal 

 with problems connected with the utilisation of forest 

 products. It was proposed that the latter should be 

 g-overned by a research board composed of official 

 and non-official members, the board being an execu- 

 tive body similar to the research boards established 

 by the Department of Scientific and Industrial 

 Research. Such a board, which would have definite 

 sums allotted to it for research on forest products, 

 would decide where any particular problem should 

 be investigated, and distribute the funds at its dis- 

 posal accordingly. 



The question of forestry education in its various 

 aspects was fully discussed, and although this ques- 

 tion presented numerous difficulties the conference 

 succeeded in clearing the ground to a considerable 

 ■extent. In approaching this question sufficient dis- 

 crimination is not always shown between the training 

 of forest officers for service in different parts of the 

 Empire and the training in forestry of owners and 

 managers of private woodlands and others who do not 

 desire to take the course of instruction required for 

 the various forest services. In the United Kingdom 

 the training of owners and managers of private wood- 

 lands is a matter of great importance in view of the 

 large proportion of such woodlands existing in the 

 British Isles. Such training, however, must be 

 carried out on somewhat different lines from the 

 training of forest officers for the various parts of the 

 Empire. So far as concerns the latter, the conference 

 held that one institution should be established in 

 Britain for the training of forest officers for the 

 United Kingdom and for those parts of the Empire 

 Avhich, for climatic or other reasons, mav be unable 



NO. 2650, VOL. 105] 



to establish such an institution of their own, or 

 desire to send students to Britain for training. 

 Students would be selected from graduates who have 

 taken honours in science at any recognised university. 

 An integral part of the work of the institution would 

 be to arrange supplementary courses at suitable 

 centres for students requiring special qualifications, 

 and also special courses for forest officers from any 

 part of the Empire, whether at the institution itself 

 or at centres of training in other parts of the world. 

 A department of research into the formation, tending, 

 and protection of forests would be associated with the 

 training institution. 



In view of the success of the conference just held, 

 and of the far-reaching results likely to follow, it is 

 proposed that this should be onlv the first of a series 

 of similar forestry conferences to be held at intervals 

 of a few years in different parts of the Empire. 

 Such conferences cannot fail" to stimulate public 

 opmion in regard to what is a very important national 

 question or to advance the cause of scientific and 

 economfc forestry, which has hitherto been too much 

 neglected by the Empire at large. 



Colloidal Electrolytes. 



r^OLLOIDAL electrolytes are defined as solutions 

 ^^ of salts in which one ion has been replaced by 

 a heavily hydrated multivalent "micelle," or cluster 

 of ions, carrying an electrical charge equal to the sum 

 of the charges of the constituent ions-, and (by reason 

 of its reduced resistance to movement through the 

 fluid) serving as an excellent conductor of electricity. 

 This new class of electrolytes probably includes most 

 organic compounds, containing more 'than eight car- 

 bon atoms, which are capable of forming ions — e.g. 

 proteins, dyes, indicators, sulphonates, and soaps; 

 it may also include inorganic compounds, such as 

 chromium salts, tungstates, silicates, etc., which have 

 a marked tendency to form highly complex ions. 

 Work on this subject has been in progress in the 

 laboratory of physical chemistrv at the University of 

 Bristol during a period of several years, and the results 

 of the investigation have recently been published by 

 Prof. J. W. McBain in papers communicated to the 

 Royal Society (Proc. R.S., 1920, A, 97, 44-65), to 

 the Chemical Society (Trans C.S., 1919, 115, 1279- 

 1300), and to the American Chemical Society. 



The earlier experiments at Bristol showed that 

 soap solutions possess a high degree of electrical 

 conductivity, not only in dilute, but also in concen- 

 trated, solutions. This electrical conductivity could 

 not be attributed to hydrolysis, since the absence of all 

 but mere traces of free alkali could be demonstrated 

 by measurements both of rate of catalysis and of 

 electro-motijv^e force. The high conductivity of the 

 solution must therefore be due to the soap itself. 

 Experiments on the depression of the freezing-point 

 of soap solutions, and later experiments on the 

 lowering of vapour-pressure, showed that, whilst the 

 salts of the simpler fatty acids have an osmotic 

 activity diminishing steadily as the concentration 

 increases, salts of the higher homologues (from C,, 

 upwards) have an osmotic activity which passes 

 through a minimum and then through a maximum 

 before finallv diminishing to a lofv value in the most 

 concentrated solutions. The high osmotic activity of 

 the soaps in concentrated solutions, coupled with the 

 remarkable electrical conductivitv of these solutions, 

 is explained most satisfactorilv by the theorv of the 

 ionic micelle. In its simplest form this micelle might 

 be merelv a polvmer of the negative radical, in a 

 strongly hydrated condition, but it is possible, and even 



