866 Proceediiigs of Societies. 



February 18.— Mr John Armstrong, Lauriston Place, was admitted 

 an Ordinary Member. 



Mr John Adie read a paper on a new construction of a Dew Point In- 

 strument, accompanied with a comparative table of observations made by 

 it, and by others previously in use. 



A model of the Rev. George Tough's apparatus for sweeping chim- 

 neys, whereby the use of climbing boys is rendered unnecessary, was exhi- 

 bited, and presented to the Society by the inventor. 



March 4. — Mr Galbraith exhibited to the Society a Turnip Extractor, 

 invented by Mr William Hume of Greenlaw, and explained the manner 

 of its application for extracting turnips from the throats of cattle. 



Mr Dunn read a paper on the escape of steam from the aperture of a 



boiler, in reference to an experiment of Clement. Mr Dunn's experiments 



- seemed to show in a very satisfactory manner, that no real danger can arise 



from the singular adhesion of a circular disc to an aperture from which a 



fluid is issuing. 



3. Proceedings of the Cambridge Philosophical Society. 



December 8, 1828. — The Rev. Professor Farish, Vice-President, being 

 in the chair, a communication was read to the society by the Rev. John 

 Warren of Jesus CollegCf stating the coincidence of the views respect- 

 ing the Algebraic Quantities commonly called Impossible Roots or Ima- 

 ginary Quantities, contained in his " Treatise on the Geometrical represen- 

 tation of the Square Roots of Negative Quantities," with those independ- 

 ently arrived at by M. Mourey, in hi* work entitled " La vraie Theorie 

 des Quantites Negatives et des Quantites pretendues Imaginaires," pub- 

 lished at Paris during the present year : and giving from these views a 

 proof, extracted from the work of M. Mourey, that every equation hqs as 

 many roots as it has dimensions. 



A communication was likewise read by Dr Thackeray, respecting a 

 young woman in the neighbourhood of Cambridge, who was stated to have 

 lived without food or the least reduction in the weight of the body, since 

 the beginning of October. 



The reading of Mr Challis's paper was also concluded, "on the exten- 

 sion to the satellites, of Bode's law of the distances of the primary planets." 

 The existence of the law in this case having been proved, it was inferred 

 that the distances may be approximately expressed in the following man- 

 ner : — 



For the Planets 4, 4 + 3, 4+3 X 2, &c. 



For Jupiter's satellites 7, 7 + 4, 7 + 4 X 2^, &c. 



For Saturn's satellites 4, 4 + 1, 4 + 1 X 2, &c. 



For Uranus's satellites 3, 3 + 1,3 + lXli^ &c. 

 It was likewise concluded from this law, that there can be no planet near- 

 er the sun than Mercury; and no satellite nearer the several primaries, 

 than the nearest of those, in each system which have been discovered. 

 The deviations from the law were also examined, and it was stated to be 



