24 Oliservations upon Luminous Animals. 
- 
traction of the planes over cach other, and on the sun. 
The verv smal! differences that still are found between the 
formulas and observations, being alternately negative and 
positive, show that no alteration is required in the value of 
the masses | have emploved. These values are thus very 
near the truth; and to rectify them, we must wait for new 
observations, which can only be procured to astronomy by 
succeeding ages. 
V. Observations upon Luminous Animals. By JAMES 
Macartney, Esq.* 
Tue property which certain animals possess of emitting 
light is so curious and interesting, that it has attracted the 
attention of naturalists in all ages. Tt was particularly 
noticed by Aristotle and Pliny amongst the ancients, and 
the publications of the different learned Societies in Europe 
contain numerous memoirs upon the subject. Notwith- 
standing the degree of regard bestowed upon the history of 
Juminous animals, it is still very imperfect; the power of 
producing light appears to have been attributed to several 
creatures which do not possess it; some species which en- 
joy it in an eminent degree have been imperfectly described, 
or entirely unobserved ; the organs which afford the: light 
in certain animals have not been examined by dissection 5 
and lastly, the explanations that have been given of the 
phenomena of animal light are unsatisfactory, and in 
some instances palpably erroneous. ; 
As th's subject forms an interesting part of the history 
of organized beings, I have for some years availed myself cf 
such opportunities as occurred for its investigation. Having 
communicated the result of some of my researches to the 
Right Hon. Sir Joseph Banks, he immediately offered me 
his assistance, with that liberality which so eminently di- 
stinguishes bim as areal lover of science. Iam indebted 
to him for an inspéction of the valuable journal he kept 
during his voyage with Captain Cook ; for permission to 
copy the original drawings in his possession, of those lu- 
minous animals discovered in both the voyages of Cook ; 
and for some notes upon the luminous appearance of the 
sea, that were presented to him by Capt. Horsburg, whose 
accuracy of observation is already known to this. learned 
Society. 
In the following paper, I shall first examine the grounds 
en which the property of showing light bas been ascribed 
% From the Philosophical Transactions far 1810, Part Il. to 
