{^30 
fccond^de Comets ; the third,^^ p£cipuu feu decumanu 7ejludimhm ; 
the fourth, de Helicoidihus, 
His Architecture Miliary iscomprifed in 7 Books; of which the 
firft laysndown the Grounds and Axioms of that Art ; thefecond is 
converfant about Regular Polygons ; the third, about Outworks 5 
the fourth,about Irreguiar Figures 5 the fifth^about Circumvallati- 
ons,Trenches,cf the fixtbjabout Defence ; the feventb^abouc Per- 
fpeflive Military. 
Jn the Hydrofiaticksy heconfiders i. the Poife of Bodies fwim- 
ming; how much Bodies lofe of their weighc,being ininiers'd in wa- 
.ter ; how Mettals may be tryed in water, and the like. 
In the Treatife of Fountains and River he difcourfes of the E- 
quipoife of Waters; of the ways of conveying Springs and Rivers; 
. of Salient waters ; of the feveral depths, which a River acquires by 
the inlet of feveral Torrents or other Waters^ &c. 
In that of Hy^rmlicks^ he treats of all forts of Artificial Foun- 
tains, that perform their efFeft either by Attraftion, or Comprefli- 
on,or Expulfion ; as alfo of all forts of Engins for raifing of Water t 
Where he gives a particular account of the great Water- whee lac ' 
Bremen^ which in every revolution fends 25 Cart-loads of Water , 
into that City .To all which he annexes the confideration of all forts 
ofMil!s,principally ofCorn-Powdcr-Paper-and Iron-Mills. 
Faffing on to Navigmon^t fpeaks r. of Ship-Carpentry ;of the 
feveral forts of Ships;of Rowing,Sayling,Steering,Loading.2.0fthe 
Makeaod Ufeof the Sea-Compafs,and the method of obferviRg,and 
allowing for,the Declination ofthe Needle. 3. Of the nature oihoxo- 
dromy^ or that Line which a Ship makes on the furface of the Terra- 
queous Glob^ by tlie duUm of the fame Rumb of the Mariners Com- 
pafs* 4* Of Sea-Maps, and divers praflices to determine the Ships 
way.^.Of the way of keeping the account of Time at Sea;where oc- 
curs a long Difcourfe about the L(?«giV«<s/^, that is, theEafterlyor 
Wefterly diftance of the Ship from the place where the Voyage be- 
gan. 6. Of divers Nautical Praflices \ as,makingof JournaIs,repre- 
fenting the Profpefts of remarkable Coafts, by making Draughts, 
Plots and Maps of them, with their Longitudes, Latitudes, Scales, 
^r.asalfo of finding the Time of the Tides,and of conjefluring tem- 
peftuous weather. 
Proceeding to Offices ^he gives an exafl: defcription ofthe Eye ; 
enumerates the various deceptions of the Sight 5 ihews the caufe of 
being long and fhort-fighted ; treats of ftriate images, which, being 
lookt on from different places, do vary ; and of defiorm piflures, 
w^hichj^ 
