CONTENTS. 



XVll 



IX. Defcription of an Hygrometer and Photometer. By Mr. John Leflie. 

 Communicated by the Inventor - - . p. 461 



If of two fimilar thermometers, the ball of one be blacked, while the glafs of the other remains clear 

 and tranTparent : the temperature of the former will be more elevated by light, than that of the 

 Intter; or if the ball of one thermometer be wetted, while the other remains dry, the evaporation 

 will diminifli the temperature of the firft. The thermometers may thus be made to indicate the ia- 

 tenfity of light, or the abforption of humidity. The inftrument of the inventor confifts of two air 

 thermometers, connefted together by a fyphon tube, in which a fluid moves, accordingly as the 

 fpring of the included air in one or the other ball is affefled, by the before mentioned caufes. 



X. Defcription of the Hydroftatic Lamp of Mr. Peter Keir - p. 467 



Obfetvations on the methods of fupplying lamps with oil. Fountain lamp ; its excellencies and defefts. 

 The lamp of Robert Hooke, which preferved the oil accurately at the fame level. Hydroftatic 

 lamp. 



XI. Refleflions on the Decompofition of the Muriate of Soda by the Oxide of 

 Lead. By Cit. Vauquelin * - - - P- 470 



Philofophical News. Accounts of Books, &c. - - P- 473 



Philofophical Tranfadlions. Lord Dundonald's Profpeftus. Sugar from the White Beet. Count 

 Rumford's Effays. Pcarfon's Chemical Nomenclature. Mudge's Defcription of a Time-Keeper. 

 Adams' Eleftricity. 



FEBRUARY I800. 



Engravings of the following Objeds : 1. Apparatus for determining the Adion of 

 Fluids ; and, 2. A Veffel for boiling inflammable Fluids. 



I. Experiments on Indigo. By a Correfpondent - P- 477 



Treatment of Indigo with inflammable bodies to deprive it of oxygen. New volatile produft of a 

 metallic afpeft, not magnetical, nor afted upon by muriatic acid nor alcohol, nor boiling cauftic 

 alkali, nor boiling concentrated fulphuric acid ; but rapidly foiuble in nitrous acid, and preci- 

 pitable of a white colour by alkalis, &c. — A fluid, having the qualities of laurel-water, produced 

 by abftrafling nitrous acid from Indigo. Applications of oxigen to Indigo, &c. 



II. New Refearchcs into the Affinities which the Earths exert upon each other 

 in the humid and dry Way. By Citizen Guyton. (Concluded from p. 42a) 



III. Concerning the Influence of the Moon on the Atmofphere of the Earth. 

 By C. Lamark - - - - p. 488 



From a feries of obfervatlons, the author prefents the following principles as ellablilhcd ; viz. that 

 while the moon has north declination, the winds in this climate are fouth, fouth-vveft, and weft, 

 with cloudy, damp, rainy, or ftormy weather; but that the oppofite winds, with clear fettled 

 weather, predominate during the fouth declination of that planet. Thefe efte<Sls are modified by 

 various circumftances, fuch as the pofidons of the moon in its orbit, its conjunftions and oppofi- 

 tions, &c. 



Vol. Ill March 1800. d V, Dt- 



