I'jz The 3\(amral Hiflory 
ftruts or braces^ as in Tah. 13. Fig, 6. muft neceffarily bend or 
break before the window can fink. Nor are the round windows be- 
low unworthy confideration, being contrived to admit air in foul 
weather, yet not one drop of rain ; for being opened and fet ob- 
liquely in Tab, 1 8. Fig, 7. it receives the rain within at a^ and 
cafts it out again at b ; much lefs will it admit rain any ways when 
Jbut^ itclofing within its/w/Tie at the top, and without it at the 
bottom. 
148. It was an excellent <^ez//Ve, who ever firft contrived it, of 
making flat floors or roofs of (Iiort pieces of Timber^ continued to 
a great bredth without either Arch -workov Pillar to fupport them, 
being fuftained only by the flde walls znd thdv own texture-, for 
by this means many times the defed of long timber^ or miftakes of 
Work-men^ are fupplyed and reftified without any prejudice to the 
Building* Of this fort of work we have an example in the Schools^ 
in the floor of the uppermoft room of the Tower^ but to be feen 
only in the room underneath where the Records of the Vniverfity 
lye. There is alfo a diagram of fuch work in the ArchiteSiure fet 
forth by Sebaftian Serly \ for which reafon I think I fhould fcarce 
have mentioned it, but that the Reverend and Learned Dr.j^ohn 
Wall^^ Savilian Profeflor of Geometry here, was the firft that de- 
monftrated the reafon of this work.-* and has given divers forms 
of it befide the fore-mentioned, in his Book De Motu^ whence I 
have taken the diagrams^ Tab. 13. Fig. 8,9, i o, 1 1 , 1 2 to make 
them more publick ; upon the two firfl whereof depend the three 
laft^ and all others of the kind what ever, whether made up of 
quadrats or ohlongparallelograms, of which there are fome other 
forms in the fore-cited Book De Motu^ befide that engraven Fig, 
10. confiftingof great and fmall Quadrats ; or Triangles zhne^ 
as Fig, II. or mixt with Hexagons^ as Fig, 12. to which Book 
I recommend the Reader for further fatisfadtion concerning them. 
149 . But of all the flat floors having no Pillars to fupport it, 
zndwhoi^e main beams are made of divers pieces of Timber, the 
moft admirable is that of the Theater in Oxford^ from fide wall to 
fide w^all 80 foot over oneway, and 70 the other,whofe Lockages 
being fo quite different from before mentioned, and in many 
other: particulars perhaps not to be parallel'd in the Worlds I have, 
taken care to reprefent an exad draught of it, Tab. 14. Fig. i. 
t Seb. Serin ArchlteWLib. i. deGeom. cap. i. »• WaUtfii Mechanica five de Motu, Parte 3. devtBe 
cap. 6. prop. 10. 
150. Where- 
