ENGRAVINGS.— CONTENTS. 



Vol. VI. is illuftrated with a Reprefentation of a remarkable 

 Efcc'tric Phenomenon obferved in a Thunder-Cloud — American 

 ilka — An improved 40 Gallon Still, which may be charged and 

 emptied upwards of Seventy Times in .'.4 Hours — An Improved 

 Still, which, even on a large Scale, may be charged and run oif 

 Four Hundred and Eighty Times every Twenty-four Hours — The 

 Urcecla E'alKca, or Caout-chcuc Vi;ie of Sumatra and Puilo- 

 pinang — Mr. Rodman's newly invented Trepanning Inurument— . 

 Mr. Collier's Filtering Machines — The Mus Buriariusr— A Plate 

 illuftrating certain Phenomena obfeivcd in the Air- Vault of the 

 Furrfaces of the Devon Iron-Works — An Air and a Water-Vault 

 for equalifing the Discharge of Air into a Blaft-Fumace. 



Vol. VII. is illuftrated with a Plate illuftrating an unufual hori- 

 zontal Refraction of the Air — Apparatus employed by Mr. 

 Howard for trying the Effects of fulminating Mercury — Plate to 

 explain the Theory of the Evening and Morning Dew — Vefpertilio 

 Plicatus — Mercurial Air-holder and Breathing Machine — Improved 

 Diililiing and Rectifying Apparatus for favit:g Fuel — Machine by 

 which the Strength of Horfea may be employed to knead Pafte for 

 Bread — Reprefentation of the Galvanic Pile and Galvanic Circle of 

 M. Volta — Meteorological Chart to illuftrate the Influence of the 

 Sun and Moon in producing a periodical Variation in 1 he Baro- 

 meter — The grand antique Bacchanalian Vafe, kte in the Poflefllon 

 of Lord Cawdor, now at Woburn Abbey ; and, Apparatus em- 

 ployed by Dr. Herfchel in his Experiments on the different fte« 

 frangibility of the Rays of Light and Heat. 



CONTENTS of NUMBER XXIX. 



Page 



I. Thoughts on Colouring, and particularly with a Retro- 

 •fprfifc to the Method ufed by the Venetians in the Mechanical 

 Part of the Art, and to their Method of Arranging the Tints 3 



II. Experiments on the Refrangibility of the inviiilJTt Rays 



of the Sun. By William Herschxl, LL.D.F.R.S. 9 



III. Experiments on the Solar and on the Terrell.) ial Rryg 

 that bccaGon Heat ; with a comparative View of the Laws to 

 which Light and Heat, or rather the 'Rays which occafion 

 them, are fubjecL in order to determine whether they ate the 

 fame, or different. By William Hbrschel, LL.D. F.R S. 16 



IV. Account of fome interefting Experiments, performed at 

 the London Philofophical Society, rcfpedling the Effe&s of 

 Heat, excited by a Stream of Oxygen Gas thrown upon ignited 

 Charcoal, on a number of Gems and other refractory Sub- 

 ftances fubmitted to its A&ion ; with a Defcription of the 

 apparatus employed « - - - c 1 



