49 



respiratory organs or Iung3 of other amphibious animals ; but a simi- 

 lar viscus he has hitherto sought for in vain in the larvae 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 Linnaeus, which has since been classed with the fishes 

 under the name of Muraena 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. 



Observations tending to investigate the Nature of the Sun, in order to 

 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,;?. 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 phae- 

 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, penumbrae, faculae, and luculi, hitherto used to denote 

 certain appearances on the sun. Those he adopts are, openings, flats, 

 ridges, nodules, crankles, shallows, dimples, and punctures. 

 E 



