1120 Biographical Memoir of Sir William .Herscliel. 
This splendid discovery excited great interest throughout all 
Europe. Sir Humphry Davy, Sir Henry Englefield, M. Ber- 
ard, and many other philosophers of distinction, repeated the 
experiments with perfect success; and Dr Wollaston, M. Rit- 
ter and M. Bockmann were conducted, during the repetition of 
Dr Herschel’s experiments, to the discovery of the chemical or 
deoxidating rays, at the opposite end of the spectrum. Amid 
the general applause with which these great accessions to science 
were received, one dissentient voice alone was heard. An indi- 
vidual whose speculations the discovery of Invisible Solar Heat 
had cast into the shade, attacked Dr Herscliel with an asperity 
far beyond the limits even of severe criticism ; but though that 
venerable man often spoke, with suppressed feelings, of the at- 
tempt which was thus made to discredit and depreciate his la- 
bours ; yet he never condescended to repel the charge ; and he 
had the satisfaction before he died of seeing his own discoveries 
universally received among the established principles of Phvsics, 
while those of his assailant were rejected by philosophers of every 
cast, both in the Old and in the New World *. 
The discoveries of Dr Herschel, which we have now recorded, 
terminated his labours in the eighteenth century, and may be 
considered as the capital of that triumphal pillar which he 
has reared for himself in the Temple of Science. He had 
now reached his sixty-second year, that period of life when the 
ambition of discovery is at least mellowed, if not in some degree 
replaced, by more serious principles of action ; and though 
he afterwards enriched the Philosophical Transactions with 
numerous communications of great value, yet they were less 
* The discoveries of Dr Herschel, respecting the Prismatic Spectrum, are con- 
tained in three Memoirs, which are printed in the Philosophical Transactions for 
1800, under the following titles : 
1. Investigation of the powers of the Prismatic Colours to heat and illuminate 
objects ; with remarks that prove the different refrangibility of radiant heat. — Phil. 
Trans. 1800, p. 255. 
2. Experiments on the refrangibility of the invisible rays of the Sun Id. p. 284. 
3 Experiments on the solar , and on the terrestrial rays that occasion heat , with a 
comparative view of the laws to which light and heat , or rather the rays which occasion 
them , are subject , in order to determine whether they are the same or different . — 
Part I. Phil. Trans, p. 293, Part II. Phil. Trans, p. 437. 
