respiratory organs or lungs of other amphibious animals; but a simi-
lar viscus he has hitherto sought for in vain in the larvæ of water
lizards or other animals of that description.
Concerning the habits of this singular animal, we learn from a friend of the author, who resides near the lake where it is found, and who had the good fortune to keep one of them alive during several days, that it seemed at all times very torpid; that though it would occasionally swim with the help of its broad tail, it was in general motionless at the bottom of the water. Sometimes it rose to the surface, stretched its head out of the water, seemed to take in air, but immediately returned to the bottom. It crept by means of its feet both at the bottom and on the side of the vessel, but so slowly that the circumstance may be thought characteristic of the animal. Sometimes, putting its head out of the water, it produced a hissing noise, louder than could have been expected from so small an animal The author, lastly, compares this singular production with the Siren lacertina of Linnæus, which has since been classed with the fishes under the name of Murana Siren, and finds a considerable analogy between the two: and though he seems unwilling to determine whe- ther the animal he describes be perfect, or only a larva of some un- known species, the facts he has adduced will probably be thought to favour the former of these opinions.
find the Causes or Symptoms of its variable Emission of Light and Heat; with Remarks on the Use that may possibly be drawn from Solar Observations. By William Herschel, LL.D. F.R.S. Read
April 16, 1801. [Phil. Trans. 1801, p. 265.]The principal object of this paper is to explore the causes or sym- ptoms of the variation we observe in the emission of light and heat from the sun.
Considering the great influence of these agents on most of the concerns of life, it is scarcely necessary to point out the importance of the inquiry: not that any discoveries we may make on the subject will ever enable us to modify their operations, but that, by a due knowledge of them, we may be guided in our own proceedings, in the same manner as we frequently are by the meteorological instru- ments, on whose combined indications we have been taught to place a certain degree of confidence.
In order to obtain as intimate a knowledge of the sun as that which is required for the purpose here indicated, it is obvious that the first step must be to become well acquainted with all the pha- nomena that usually appear on its surface: and this accordingly is the subject of the first part of the present paper. Dr. Herschel pre- mises his reasons for substituting a new set of names for those of spots, nuclei, penumbræ, faculæ, and luculi, hitherto used to denote certain appearances on the sun. Those he adopts are, openings, flats, ridges, nodules, crankles, shallows, dimples, and punctures.
