VIU 



CONTENTS. 



Hydranlic Phenomena. By Citizen J. B. Venturl, Profeflbr of Experi- 

 mental Philofopliy at Modena, Member of the Italian Society of the Infti- 

 tute of Bologna, the Agrarian Society of Turin, &c. — P- 172 



Apparatus defcribedi — Newton's general affirmation concerning the lateral motion of fluids, does not 

 apply to a jet at the I'urface of ftill water. Experiments fliewing that the adjacent fluid is carried 

 along with the ftream. On the contrafted part of a jet. ' The efflux is increaled by fuffering the 

 ftream to pafs through an additional tube in any direftlon whatever This increafe is in all the 

 cafes owing to the prefliire of the atmofphere. Experiments ; by admitting the atmofphere into the 

 tube ; — by a kind of barometer; — and by an apparatus in vacuo On the expenditure through ver- 

 tical additional tubes. It is the lame as correfponds with the height of the tiuid above the lower 

 extremity of the tube. Proof. Experiments with fimple apertures, verticle tubes, and horizontal 

 tubes. Efie£ls of frittion ; and of vifcidity. 



VIII. Experiments and Obfervations on the EfFe£l of annealing a Plate of 

 Metal, confining of fine or alloyed Gold, with one Twenty-fourth Part of 

 Tin. By Mathew Tillct — — — P- '79 



Alloy of gold of 32 carats and one twenty-fourth of tin in large quantities. It proved rigid, though 

 malleable, but falls to pieces in the fire by a low red heat, and confequently is unfit for gold-workers. 

 Various experiments chemical and mechanical. Fine gold alloyed with tin has the fame defe6l. It 

 ariles from the great fufibility of the tin. 



IX. On the Knowledge of the Ancients refpecting Gravity. By a Corre- 

 fpondent — — — — — p. 184 



Quotation from Plutarch. Remarks. 



X. A fhort Mineralogical Defcription of the Mountain of Gibraltar. By 

 Major Imrie — — — — — P- 185 



Dhnenfions and compofitlon of the Rock of Gibraltar. Its caverns. Phenomenon which fliews that 

 water formerly covered this rock. 



Account of New Books — — — — p. 188 



Memoirs of the Literary and Phllofophlcal Society at Maiichefter, Vol. V.— Tranfaftions of the Royal 

 Society of Edinburgh, Vol. IV. 



AUGUST 1798. ■ 



Engravings of the following Objefts : i. An Economical Laboratory, by Guy- 

 ton. 2. Sketch of the Gold Mine in the County of Wicklovv, in Ireland. 

 3. A very fimple Apparatus for performing the Combuftion of Oxygen and 

 Hvdrogen, by Cuthbcrtfon. 4. A New Steam Engine, operating by the 

 joint Powers of Steam and the Atmofpheric PrefTure, by James Sadler, 

 £fq. . 



I. Far- 



