836 



SCIENCE. 



[N. S. Vol. III. No. 75. 



cultivated." This method of garden cul- 

 ture is stimulated by societies which furnish 

 lectures to the masses, publications in the 

 shape of primers, etc. This portion of Mr. 

 Dean's work will be particularly appreciated 

 by those who are interested in a similar 

 work for the city poor in this countrJ^ 



The work before us is interesting in its 

 classification of the products, or rather the 

 crops of the garden. The first group is the 

 tap and bulbous-rooted vegetables, including 

 beets, carrots, onions, celeriac, turnij), etc., 

 followed by tuberous-rooted vegetables, of 

 which the potato is the leading example. 

 Under pod-bearing vegetables are peas and 

 beans, and the fruit-bearing vegetables in- 

 clude squashes, cucumbers, tomatoes. Cab- 

 bage and spinach are under green vegeta- 

 bles, while of edible stemmed plants, as 

 asparagus, rhubarb and celery and repre- 

 sentatives, and also the mushroom. 



The handbook is quite English in the 

 varieties it recommends, and the calendar 

 for operations does not coincide with the 

 one for our climate and seasons. 



Byron D. Halsted. 



SCIENTIFIC NOTES AND NEWS. 



THE METRIC SYSTEM. 



Appleton's Popular Science Monthly for June 

 reprints the letters contributed anonymously 

 by Mr. Herbert Spencer to the London Times, 

 and endorses their point of view in an editorial 

 article. The Monthly cannot but be admired 

 for its allegiance to Mr. Spencer even in his 

 vagaries, but it must be regarded as unfortunate 

 that a journal whose readers \\\\\ expect to find 

 it represent the consensus of opinion of men of 

 science should advocate the prejudices of the 

 uninformed. We are not surprised to find that 

 part of Mr. Spencer's contribution was written 

 fifty years ago, and that the authorities he 

 quotes are Sir John Herschel's article of 1863 

 and Prof. H. A. Hazen. But it was not to be 

 expected that Mr. Spencer would confuse the 

 metric and a decimal system, and argue that 

 the former should not be adopted because the 

 calendar cannot conveniently be divided deci- 



mally. Can the week be divided into quarters, 

 eights and thirds, which Mr. Spencer rightly 

 regards as desirable ? If our ancestors had had 

 twelve fingers in place of ten we should now 

 have a better system of numeration, but the 

 ideal and distant day, when we shall all do 

 what is most reasonable, can be brought nearer 

 by acting reasonably in the present and adopt- 

 ing the admirable system so rapidly becoming 

 universal. For as Sir John Herschel wrote in 

 1863, "Were the question an open one what 

 standard a new nation, unprovided with one 

 and unfettered by usages of any sort should 

 select, there could be no hesitation. ' ' 



THE RONTGEN RAY'S. 



Nature gives an account of early experiments 

 on the Eontgen rays by Prof. A Battelli and Dr. 

 A. Garbasso, of Pisa. Keferring to the dis- 

 covery that the time of exposure required for 

 taking photographs with these rays can be 

 greatlj'' shortened bj' placing certain fluorescent 

 substances behind the XDhotographic plate, the 

 authors point out that they described a method 

 of doing this in the January number of // Nuovo 

 Cimento. In some cases Prof. Battelli and Dr. 

 Garbasso obtained good photographs with an ex- 

 posure of only two seconds. In their paper 

 experiments were also described proving that 

 Kontgen 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 communi- 

 cated 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 

 from the anode or cathode, also that they are 

 emitted even after the discharge in the tube has 

 ceased (as proved by the discharge of an elec- 

 trified disc in the neighborhood of the tube). 

 In the second paper Prof. Battelli deduces that 

 the rays which emanate from the cathode in a 

 vacuum tube possess photographic properties ; 

 that their action increases as the rarefraction 

 increases (at least up to j^u mm. of pressure); 

 and that some of the rays 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. 



