356 PHILOSOPHICAL TRANSACTIONS. [aNNO 1794. 



In all the best maps of the Kattegat, as that by Mr. Lous, published at 

 Copenhagen, 1790, that by M. Verdun de la Crenne, M. Borda, and M. 

 Pingre, Paris, 1778, that by Mr. Akeleie, Copenhagen, 1771, that by Mr. 

 Ankerkrona, Stockholm, 1782, the position of Anholt is very erroneous. The 

 light-house of Anholt, and the whole isle, is from 7 to 9 minutes too much 

 westerly ; and the distance from the light-house to the Swedish coast, in a direc- 

 tion perpendicular to the meridian of the light-house is, in all maps hitherto 

 published, nearly 4 English miles, or -f part of the whole too great. Experience 

 has taught the navigators that they come too soon down on Anholt ; or that they, 

 cruising between Anholt and Sweden, overrun their reckoning, which was 

 ascribed to the currents ; though the true reason of it was the great error in the 

 geographical and hydrographical position of Anholt in a narrow and dangerous 

 passage. 



VIII. On the Rotation of the Planet Saturn on its ^xis. By Wm. Herschel, 



LL. D., F. R. S. p. 48. 



In a late paper on the multiplicity of the regular belts of the planet Saturn, 

 says Dr. H., I pointed out an analogy which might lead us to surmise that it had 

 a pretty quick rotation on its axis ; I can at present announce the reality of that 

 rotation. The following series of observations, in which Saturn has been traced 

 through 154 revolutions of its equator, will sufficiently confirm it. The changes 

 in the belts of Jupiter, it is well known, are so frequent, that we find some 

 difficulty to make our observations of them agree to within 3, 4, or 5 minutes 

 of time ; but the belts on Saturn, which I have been lately observing, seem to 

 have undergone no very material change during the course of the last 2 months ; 

 so that we may hope the period of the rotation of this planet, which will be 

 assigned in this paper, may be considered as having a considerable degree of 

 exactness. 



Before we can enter into particulars, it will be necessary to give the series of 

 observations on which the computations have been founded. It is not sufficient 

 to extract only those parts of them which have served for calculating the period ; 

 as the value of astronomical observations consists in having them entire ; every 

 circumstance, as it occurred, is of consequence, and, facts being stubborn things, 

 we cannot decide on them properly till they have been entirely laid open to our 

 view, and sufficiently scrutinized. For this purpose the observations are all 

 extracted from the journal in the regular order in which they were made ; and 

 here I must remark, that I purposely avoided any calculations, or even surmises, 

 of the length of a rotation, while the observations were making ; in order to be 

 perfectly free from every bias that might mislead the eye. In tliis I succeeded 



