62 



NA TURE 



[May 21, 1896 



Black says a friend of his recently had his meteorological 

 instruments upset and kicked about by Irish miners working in 

 Lanarkshire. But the exuberance of spirits which led to this 

 destruction is not confined to Irishmen, for Mr. Black says that 

 at Duddingston Loch, some time ago, a number of Bank Holiday 

 savages upset a complete meteorological equipment into the 

 water near which it was installed ; while in several northern 

 towns it is necessary to enclose the instruments in iron cages to 

 preserve them from being used as targets by the demon boy. 

 Probably much of the destruction is the result of sheer wanton- 

 ness, but anthropologists might be able to find evidence that 

 the instruments are considered uncanny, in which case we 

 .should have to confess to the survival of the mediiv val super- 

 stition against meteorology. 



Most workers with Rontgen rays have observed that a photo- 

 graphic plate becomes more or less fluorescent when the rays 

 fall upon it. Mr. W. J. D. Walker informs us that a Paget 

 X .\ X X X plate used by him fiuorised so decidedly, that it made 

 a very fair fluorescent screen, capable of showing coins in a 

 purse, the bones of the fingers, screws and nails in a wooden 

 block, and similar objects. 



A NUMBER of excellent Rontgen photographs received from 

 Mr. H. S. Pyne, of King William's College, Isle of Man, show 

 that the Wimshurst machine is capable of producing effects com - 

 parable with those given by means of a good induction coil. 

 The machine employed had plates fifteen inches in diameter, 

 and the best results were obtained when the discharge was made 

 intermittent. By this means the tube is rested, and, even with 

 a quarter of an hour's continuous work, the phosphorescent area 

 does not become appreciably warm. A Newton's " focus " tube 

 was used, and the definition of the pictures produced by its 

 radiations is exceedingly good and .sharp. All the plates used 

 were " Ilford rapid," with the exception of one, being a 

 " Cadett" lightning. The latter plates Mr. Pyne has found to 

 require the least exposure. 



The peculiar glow exhibited by a " focus " tube working well 

 furnishes a good criterion of efficiency as regards Rontgen rays. 

 A more definite means of comparing the actinic power of the 

 radiation has been produced by Messrs. Reynolds and Branson, 

 Leeds. .\ small quadrant of aluminium is constructed in con- 

 centric terraces, ranging from one millimetre to ten milli- 

 metres in thickness. By holding this quadrant between an 

 excited Crookes' tube and a phosphorescent screen, the thick- 

 ness of aluminium which the rays are capable of traversing can 

 be seen upon the screen ; or, by substituting a sensitive plate 

 for the screen, the effect may be photographed. The " .\-ray 

 meter," as the quadrant is called, thus furnishes an easy means 

 of comparing the intensity of Rontgen rays emitted by different 

 tubes and by the same tubes at different times. 



From Prof A. Battelli and Dr. A. Garbasso, of Pisa, we have 

 received several interesting papers describing their experiments 

 on Rontgen rays. Referring to the discovery that the time of 

 exposure required for taking jihotographs with these rays can 

 be greatly shortened by placing certain fluorescent substances 

 behind the photographic plate, the authors point out that they 

 described a method of doing this in the January number of // 

 Nuo-c'o Cimento. In some cases Prof. Battelli and Dr. Garbasso 

 obtained good photographs with an exposure of only two 

 seconds. In their paper, experiments were also described 

 proving that Rontgen rays can be reflected (or at any rate 

 scattered) from surfaces, but indicating an absence of refraction. 

 Since the appearance of the above paper. Prof. Battelli has com- 

 municated two further papers to the same journal. In the first, 

 the author arrives at the conclusion that Rontgen rays behave as 

 if they emanate from the base of the vacuum tube rather than 

 NO. 1386, VOL. 54] 



from the anode or kathode, also that they are emitted even af^er 

 the discharge in the tube has ceased (as proved by the discharge 

 of an electrified disc in the neighbourhood of the tube). In the 

 second pajier. Prof. Battelli deduces that the rays which emanat 

 from the kathode in a vacuum tube possess photogrsphic 

 properties ; that their action increases as the rarefaction increases 

 (at least up to w^^ mm. of pressure) ; and that some of the ray 

 are deflected by a magnet, while others are not. It is hence 

 quite permissible to maintain that Rontgen rays exist in the 

 interior of the tube. This view does not contradict the result 

 that the rays appear to have their origin at the point where 

 kathodic rays meet with an obstacle. It is easily seen that such 

 an obstacle would act on the rays either as a filter or by s:attering 

 them in all directions. 



The various manurial trials conducted on behalf of Lie County 

 Councils of Cumberland, Durham, and Northumberlard in 1895, 

 form the subject of a report by Prof. Somerville, of the Durham 

 College of Science. Results of experiments on turnips, con- 

 ducted at twelve centres, are considered to give a dePnite answer 

 to the question as to whether it is the potash, the magnesia, 

 or the salt in kainit that determines its value, its efficacy being 

 attributed to the potash, which is the only substance that has 

 consistently increased the average crop in these trials. No poin 

 has been more clearly demonstrated in the field trials of the last 

 few years than that large dressings of dung or artificial manures d 

 not increase the turnip crop to the extent usually supposed. It 

 argued that they would be more effective if they were applie 

 in small quantities to each crop in the rotation as it came t 

 occupy the land, instead of being, as at present, put into the 

 land, say, eyery four years, to be exposed to all the wastefu 

 agencies that may operate upon them till the plant food that 

 they contain is exhausted. Manurial reform would seem to be 

 most needed in the case of the artificial manures, since, for the 

 incorporation of dung with the soil, the root-break offers facilities 

 such as are afforded by no other crop in the rotation. The 

 report includes details of experiments with finger-and-toe i 

 turnips, and with boiiillie bordelaise as a check upon potato 

 disease. 



The report of the field experiments carried out in 1895 -^X 

 the Agricultural Department of the University College of Nor 

 Wales, Bangor, under the auspices of the County Councils of 

 Anglesey, Carnarvon, Denbigh, Flint, and Montgomery, forms 

 a brochure of some fifty pages. The experiments were con- 

 cerned with the manuring of swedes, of pasture land, and of 

 hay fields, the growth of oats from different quantities of seed, 

 and the effects of various manures on the growth of vegetables. 

 The work was conducted at more than tliirty distinct centres, 

 scattered over the five counties, and the question arises as to 

 w-hether this is not too diffuse an application of energy to afford 

 the best results. It is stated that within the last eleven years 

 the trials " have gone on increasing until the number of centres 

 has almost reached forty. " Some of these places are nearly 

 150 miles apart, and many are far removed from railways. It 

 is, however, correctly understood that these field trials are 

 really intended to serve the purpose of object-lessons, "in 

 which conclusions arrived at elsewhere may be made use of 

 for the benefit of particular districts." There is considerable 

 variation in the results obtained from the use of the same 

 manures when applied to hay and pasture lands in different 

 parts of North Wales. Phosphatic manures have proved the 

 most satisfactory, and of these the most economical manure in 

 the majority of cases was basic slag. The experiments, which 

 must have involved a large amount of work, were conducted 

 by Messrs. T. Winter, Bryner Jones, R. H. Evans, and F. V. 

 Dutton. Every care should be taken to secure exactitude in 

 such reports as this, intended for circulation amongst farmers 



