; seedlings, 
May 25, 1871] 
NATURE 69 

Force and Energy 
I HAVE been under the impression that the supposed magnetising 
power of the more refrangible of the solar rays, as first examined 
by Mrs. Somerville in 1826, had been long ago disproved by the 
researches of Moser and Riess. This appears, however, to be a 
mistake, for I see from the report (in a recent number of the 
Illustrated News) of a lecture on Force and Energy lately 
delivered at the Royal Institution by Mr. Charles Brooke, 
F.R.S., that the lecturer is stated to have quoted the results of 
Mrs. Somerville’s experiments to ‘‘show the interchange of 
light and magnetic energy.” 
Is it too much to ask that the editor of a popular treatise on 
natural philosophy will give us his authority for a statement so 
contrary to general scientific opinion ? EXxACTITUDE 

Pangenesis 
DOUBTLEsS it is owing to a slight misprint in my communi- 
cation in your number of May 11 that your correspondent, Mr. 
Meldola, has mistaken the gist of my objection to the theory 
of Pangenesis. I wrote, ‘‘a seed borne upon the graft 
would certainly be affected by the gemmules arising in the 
rcot and stem of the stock;” this was printed ‘fa bud 
borne,” &c. Now although it seems to me that much has 
been done to show that the stock will occasionally affect parts 
of the scion—and this my former letter does not for a moment 
contest—no evidence whatever has been brought to show that 
the sexual elements produced upon the scion have ever been 
affected by the stock without any intermediate change in the 
parts of the scion which may have borne the affected pollen 
grains or ovules.* And this certainly ought to be shown before it 
is assumed that every bud and every sexual element is formed 
by the aggregation of gemmules from all parts of the parents. 
Instead of which, in the vast majority of instances, we know 
that seeds borne upon the scion spring true to the scion. And if 
any instances to the contrary could be shown, it would then have 
to be proved that the part of the scion that bore the reproduc- 
tive element was not a graft-hybrid. I may especially refer 
your readers to an interesting article by Dr. Masters, in the 
Popular Science Review for April, on ‘Grafting, its consequencs 
and effects.” 
A. C. RANYyARD 


STR FOHN HERSCHEL 
oR nearly one hundred and fifty years Europe has 
not seen a more accomplished philosopher than the 
great and good man whose mortal remains were last week 
consigned to their tomb in the national mausoleum, 
finding there a significant resting-place close to the grave 
of Newton. In sorrow and friendly reverence they were 
followed thither by nearly all that England values as the 
most eminent in the various domains of those many 
sciences which he, through a long life, had adorned and 
advanced. 
John Frederick William Herschel was born at Slough, 
in the early part of 1792, being the only son of that great 
philosophical astronomer, of whom it were difficult to 
decide, and one cares not to inquire, whether the father 
was or was not even more illustrious than the son. Thus 
the boy was nurtured within sight of that remarkable 
telescope, wonderful indeed for the day of its construction, 
which, though in reality among the least of Sir William’s 
achievements, had probably contributed the most to 
render the name of Herschel famous among men. His 
education was conducted chiefly at home, or at all events 
under home influences, and mainly in the society of per- 
sons considerably advanced in years ; and it is probably 
to this circumstance that we may attribute much of that 
singularly retiring, though kindly and affectionate dispo- 
sition, for which he was so greatly esteemed by all who 
had the privilege of his acquaintance. 
In 1809 he was removed to St, John’s College, Cam- 
* TI should much like to learnif the Bizzaria orange can be propagated by 
Cytisus Adami is, I believe, always sterile. 

bridge, where there are still retained among a few of its 
oldest members some curious traditions of his scrupulous 
attention to the duties of his position. Certain specified 
selections from the “Principia” of Newton formed of 
course a portion of the curriculum of study; in that day 
they came to the student in the form of manuscripts, 
translated and somewhat modified from the Latin text ; 
John Herschel, however, conceived it his duty to read the 
entire work just as Newton had left it. We mention this 
circumstance solely because it furnishes us with an early 
indication of that staple quality of mind without which no 
true greatness is ever attained, namely, thoroughness of 
work, It is not surprising that such a man carried off the 
highest honours in the University examination, and that 
in 1813 he graduated as Senior Wrangler of the year; 
the first among a little phalanx of eminent men, than 
whom the University of Cambridge has seen nothing 
superior and not much that is comparable since. 
His early lot at Cambridge was cast in times ofa scien- 
tific transition. To the majority of Englishmen the Conti- 
nent had long been sealed, and our few men of science 
were for the most part unacquainted alike with the 
languages and with the learning of the rest of Europe ; 
indeed, it is scarcely too much to say that the science of 
mathematics in England had made very little advance 
beyond what had been known in the later years of Newton. 
John Herschel, however, possessed the great advantage 
of living in a house where the chief languages of the Con- 
tinent were understood, and in which relations with abroad 
were still maintained. To the late Prof. Woodhouse the 
honour is due of having introduced to the notice of the 
Cambridge mathematicians the higher methods of analysis 
which had long been practised on the Continent, and he 
was soon ably seconded in his efforts by the young mathe- 
matician. In conjunction with his friend Mr. Peacock, 
who afterwards became the well-known Dean of Ely, John 
Herschel, in the year 1816, produced a Treatise on the 
Differential Calculus, for the use of the University, by re- 
casting rather than by translating a valuable work by 
Lacroix on that important subject, which hitherto had been 
studied in England solely to the most meagre extent, and 
encumbered by the unwieldy garb of the fluxional nota- 
tion. This work was written in 1816, and before Herschel 
had taken his master’s degree. In 1820 the translation of 
Lacroix was followed by another and more original work, 
containing a set of admirable examples and comments on 
almost all the more important methods of analysis by 
which mechanical and astronomical science had been so 
greatly extended by Newton’s real successors, such as 
Euler, Lagrange, and Laplace. In this work Herschel 
was assisted not only by Mr. Peacock, but also by Mr, 
Babbage, who wrote that part of it which treated on 
functional equations. This admirable introduction to the 
higher forms of analysis is scarcely superseded even at 
the present day, and in some respects it remains unique. 
Thus John Herschel was instrumental in the promotion 
of that great reform in mathematical culture at Cambridge, 
which has never since ceased to bear most notable and 
excellent fruit. 
It was shortly after his degree that we find the elder 
Herschel in one of his latest communications to the Royal 
Society referring with evident satisfaction to the fact that 
he had a son who was now capable of taking an important 
part in those astronomical, or rather as they may more pro- 
perly be called, those cosmical researches which had formed 
the successful pursuit and the delight of his own life ; 
and before his death he had the pleasure, we might not 
improperly call it the reward, of seeing his son in the year 
1820 become one of the honorary secretaries of the newly- 
formed Astronomical Society. For fifty years and more 
he continued to be one of its most constant and loyal 
supporters, employing some of the last conscious moments 
of his life in compiling for its service a complete list, or, if 
we may be allowed the expression, a complete natural 
