(850) 
47. Of an attempt made to meafure the Force of the Spring of 
included Air, and examine a Conje&ure of the difference of its 
ftrength in unequally broad-mouth'd Velftls. 
. 48. About an eafie way of making a fmall quantity of inclu- 
ded Air raife in the exhaufted Receiver 50 or 60 pounds, or a 
greater weight. 
49. Concerning the Weight of Air,and the eftimating that- 
of, both by thehelpof a feal'd Bubble, and by weighing the 
Receiver it felf : together with an Advertifement of the Variati- 
on of the Gravity of the Air- and that, by Experiments made at 
different times or places , there are obtained different proportions 
betwixt It and Water. 
50. About the disjoyningof two Marbles (not otherwife to 
bepull'd afunder without a great weight) by with-driawing .the 
Pre/rureof the Atmofphere. 
Which Experiments are , where 'twas necejjarj^ illuftrated 
with Figures, to the number of 30 in 8 Plates. 
The whole is concluded with fome Notes and Trials about 
the Atmofpheres of Confident Bodies (here below) ihewing, 
that even Hard and Solid Bodies f and fome fuch, as one would 
fcarce fufpeft) are capable of emitting Effluvia , and fo of ha- 
ving Atmofpheres - 7 which is prov'd firft a priori , both by the A- 
tomical and Carte fian Hypothefis and then demonfttated by 
particular Examples in feveral Bodies : where,inftancing in t-hofe, 
that are moft fixt ^ the Author examines the Argument of Des- 
cartes againfl: Eleffrical emanations , drawn from the fixednefs 
of Glafs. 
Whereunto are fubjoyned not only fome Obfervations about 
the Electricity of Bodies , as that of Amber by the Sun 5 and 
that of Glafs by the Heat of the Fire 5 but alfo fome Confi- 
derations, that may induce us to believe , that very many other 
Bodies , not yet difcover'd to do fo, emit their Effluviums. 
II. HYDRO LOGIA C H Y M I C A , or , The Chymical 
Anatomy of the S C A K B ROUGH and other fparvs in 
YoRK-S HIRE, &c. by W. SYMPSON. London, 
1668. in 8\ 
TN this Curious and Experimental Treatife the Reader will 
Fir (I m*et with fome Animadversions upon Dr. Witties Trad 
of the Scarbrougb-Sfaw $ our Author affirming , that upon 
bringing 
