36 EEPORT 1881. 



Losclimidt, wlio has since been confirmed by Stoney and Sir "W. Thom- 

 son, calculates that each is at most s-ooo^oot;? °f ^^ inch in diametei'. 



We cannot, it would seem at present, hope for any increase of our 

 knowledge of atoms by any improvement in the microscope. With 

 our present instruments we can perceive lines ruled on glass -^ olo o ^H 

 of an inch apart. But, owing to the properties of light itself, the 

 fringes due to interference begin to produce confusion at distances of 

 _,^i.g-^^ and in the brightest part of the spectrum at little more than 

 ^-j.i.^-^th they would make the obscurity more or less complete. If indeed 

 we could use the blue rays by themselves, their waves being much 

 shorter, the limit of possible visibility might be extended to jrWji-uv '■> ^^^ 

 as Helmholtz has suggested, this perhaps accounts for Stinde having 

 actually been able to obtain a photographic image of lines only xTTTmrTyt^^ 

 of an inch apart. It would seem then that, owing to the physical 

 characters of light, we can, as Sorby has pointed out, scarcely hojje 

 for any great improvement so far as the mere visibility of structure is 

 concerned, though in other respects no doubt much may be hoped for. 

 At the same time, Dallinger and Royston Pigott have shown that, so 

 far as the mere presence of simple objects is concerned, bodies of even 

 smaller dimensions can be perceived. 



According to the views of Helmholtz, the size of the smallest particle 

 that could be distinctly defined, when associated with others, is about 

 -g-jj^Tj^th of an inch. Sorby estimates that a particle of albiimen of this size 

 contains 125 millions of molecules. In the case of such a simple compound 

 as w.ater the number is 8,000 millions. Even, then, if we could construct 

 microscopes far more powerful than any we now possess, they would not 

 enable us to obtain by direct vision any idea of the ultimate molecules 

 of matter. Sorby calculates that the smallest sphere of organic matter 

 which coiild be clearly defined with our most powerful microscopes would 

 contain many millions of molecules of albumen and water, and it follows 

 that there may be an almost infinite number of structural characters in 

 organic tissues, which we can at present foresee no mode of examining. 



The Science of Meteorology has made great progress ; the weather, 

 which was formerly treated as a local phenomenon, being now shown to 

 form part of a vast system of mutually dependent cyclonic and anti- 

 cyclonic movements. The storm-signals issued at our ports are very 

 valuable to sailors, while the small weather-maps, for which we are mainly 

 indebted to Francis Galton, and the forecasts, which anyone can obtain 

 on application either personally or by telegraph at the Meteorological 

 Office, are also of increasing utility. 



Electricity in the year 1831 may be considered to have just been 

 ripe for its adaptation to practical purposes ; it was but a few years 

 previously, in 1819, that Oersted had discovered the deflective action 

 of the current on the magnetic needle, that Ampere had laid the founda- 

 tion of electro-dynamics, that Schweizzer had devised the electric coil or 



