January 2, 1908J 



NA TURE 



otosest research, and then by men who have had a train- 

 ing of such a kind that their critical faculties are strongly 

 developed. It cannot be too strongly impressed upon 

 employers how much more valuable an apprentice would 

 be were he to have an opportunity of continuing his 

 mental training in the laboratories of our well-equipped 

 colleges after having first been impressed with the real 

 problems of his calling by some years in engineering- 

 works. 



The plan sug-gested above can only be carried out with 

 the help of the employer. His works may at first suffer 

 some disorganisation, but he must see that this is a 

 national problem, and that plan of training can only be 

 the best which results from cooperation with the engineer- 

 ing colleges, even although such a system involves some 

 personal sacrifice. 



There must be something radically wrong with a system 

 of apprentice education which appears to be quickly bring- 

 ing British engineers to the position of manufacturers, 

 under license, of foreign inventions. It is quite evident 

 that by allowing a student to undergo considerable work- 

 shop experience before attending his final college course 

 the trained engineer of moderate ability would be a sounder 

 man. while the clever man would have an opportunity of 

 exploiting his capacity for research work. It must, how- 

 ever, be insisted upon that the proper education of our 

 young engineers depends altogether upon the attitude of 

 the employers towards it. If they do not realise the 

 national significance of such higher scientific training as 

 is here contemplated, it is useless for the heads of our 

 colleges to devote attention to schemes of study capable of 

 promoting it. 



In designing the laboratories of the Glasgow and West 

 of .Scotland Technical College, provision has been made 

 for the comparatively large number of older students 

 attending the final courses in engineering by putting in a 

 number of machines adapted for research work. The 

 illustration shows one corner of the laboratory devoted to 

 motivi-power engineering. 



AMERICAS INVESTIGATIONS ON ELECTRO- 

 LYTIC CONDUCTIVITY} 



'T'HE two monographs here noticed owe their existence 

 principally to the means placed at the disposal of 

 American workers by the Carnegie Institution of Wash- 

 ington. Without such aid these extensive systematic re- 

 searches could scarcely have been undertaken, and their 

 publication, unless in abbreviated form, would have pre- 

 sented considerable difficulties. 



The report by Prof. Noyes on the work of himself and 

 his collaborators is of the utmost value to all those who 

 are interested in problems connected with the conductivity 

 of aqueous solutions, salt-hydrolysis, and the like. The 

 main object of the research was to obtain accurate values 

 for the electrical conductivity of solutions in a range of 

 temperature from o° to 300°, and the chief difficulty ex- 

 perienced w-as in the construction of a conductivity vessel 

 which should be at once capable of resisting the high 

 vapour pressure of solutions up to the critical point of 

 water, and of yielding only traces of conducting impurity 

 to the aqueous solutions it contained. Bv three years of 

 patient labour Prof. Noyes and Dr. Coolidge succeeded in 

 constructing a platinum-lined bomb with insulated elec- 

 trodes, which even at high temperatures and with salt- 

 solutions as dilute as 00005 normal gives conductivity 

 measurements accurate within 0-2 per cent. With this 

 apparatus the conductivities of typical substances were 

 measured, the results obtained being given and discussed 

 in detail in the report. The substances embraced in the 

 Investigation are the chlorides of sodium, potassium, and 

 ammonium, the nitrates of silver and barium, the sulphates 

 of potassium and magnesium, the acetates of sodium and 

 ammonium, the hydro.xides of barium, sodium, and 

 ammonium, and, finally, hydrochloric, sulphuric, nitric, 



1 "The Electrical Conductivity of Aqueous Solutions." By Arthur 

 A. NovM. Pp. vi + m. (Washlneion; Carnegie Institution, 1907.) 



"Conducliviiv and Viscosiiy in Mix»d Solvents." By Harry C. Jones. 

 Pp. v + 235. (Washington ; Carnegie Institution, xt^z-j ) 



phosphoric, and acetic acids. In order to obtain data for 

 calculating the ionisation constant of water, the con- 

 ductivities of diketotetrahydrothiazole and its ammonium 

 salt were also measured. The value of this constant as 

 so determined agrees well with that obtained by Kohl- 

 rausch from the conductivity of pure water. Two special 

 sections deal with the solubility of silver chloride, bromide, 

 and thiocyanate at 100°, and with the transport numbers 

 of nitric acid. From the last section it appears that the 

 ratio of the velocity of the anions to that of the hydrogen 

 ion is several per cent, larger at very small concentra- 

 tions than at moderate concentrations, and not constant 

 for all solutions more dilute than 005 normal, as is usually 

 assumed. 



Prof. Jones, of the Johns Hopkins University, has for 

 a considerable number of years busied himself with the 

 study of solutions, especially from the standpoint of the 

 so-called hydrate theory, which in its present aspect differs 

 greatly from the theory which went under that name some 

 fifteen or twenty years ago. In this communication Prof. 

 Jones and his co-workers give the results of their investi- 

 gation of the conductivity and viscosity of certain electro- 

 lytes in water, methyl alcohol, ethyl alcohol, acetone, and 

 in binary mixtures of these solvents. The connection 

 between the fluidity of a conducting solution and the value 

 of its electric conductivity has long been recognised, but 

 comparatively little detailed experimental work has been 

 done on the subject, so that the present research, which 

 shows the close parallelism between the two properties, 

 not only for aqueous, but for other solutions, is of much 

 interest and value. The problem of the variation of con- 

 ductivity with change of composition of the solvent is 

 extremely complex, but the authors may be said to have 

 laid a safe foundation for the theoretical treatment of the 

 subject. 



THE TUBERCULIN TEST FOR CATTLE. 



"TTHE unsatisfactory nature of the tuberculin test for 

 cattle is emphasised in two articles published in the 

 " Live Stock Journal Almanac " for 1908. Mr. Bruce re- 

 marks that when an animal reacts there is no indication 

 whether the case is serious or not ; that an animal which 

 reacts freely may, when tested a month or two later, fail 

 to do so ; that change of place, of companionship, and of 

 diet, the advent of oestrus, or, in fact, anything calculated 

 to excite the animal or upset its digestive system, may 

 render the test abortive. 



Mr. Thornton records that testing cows in calf is apt 

 to bring on abortion, and adds that in Germany the test 

 is considered untrustworthy, because of the number of 

 slaughtered animals proved to be tuberculous which have 

 passed the test, and the number in which no tubercle could 

 be found which have been condemned by the test. He 

 concludes, however, with the resignation common among 

 breeders when dealing with such matters : — " The test is 

 naturally upheld bv many veterinary surgeons, and there 

 is not much probability of it being discontinued, as 

 members of the profession are generally selected as advisers 

 to the Boards of .'\griculture in the colonies and foreign 

 countries," and he might have added in this country also. 



With such facts before them, with the knowledge that 

 the disease is not necessarily hereditary, that it is by no 

 incans so infectious as has been supposed, and that it is 

 not so largely responsible for the spread of tuberculosis 

 among human beings as we were at one time led to 

 believe, one can hardly blame breeders if they show un- 

 willingness to accept the doubtful blessing of the tuberculin 

 test. 



In an article on hybrids, Mr. C. T. D.avies complains 

 that the term hybrid is often loosely applied by Mendelians 

 and other experimentalists who have little knowledge of 

 practical breeding, to the offspring of two varieties sprung 

 from the same stock. He points out that " cross-bred.s " 

 is the term practical breeders use for such produce, while 

 " hybrid " is used to designate the progeny of two distinct 

 species. He expresses the hope that biologists will adopt 

 the ancient form of nomenclature, and so avoid confusion 

 in the minds of those of their readers who are practical 

 men. 



NO. 1992. VOL. 77] 



