92 S Y L V A BOOK in 



long, because of the different intervals of rafters : 

 That of five has 100 to the bundle, those of four 1 20; 

 and to be in breadth i inch and J, and half inch thick; 

 of either of which sorts there are three, viz. heart- 

 oak, sap-lathes, and deal-lathes, which also differ 

 in price : The heart-oak are fittest to lie under 

 tyling ; the second sort, for plastring of side-walls, 

 and the third for ceilings, because they are streight 

 and even. 



17. Here we will gratifie our curious reader with 

 as curious an account of the comparative strength and 

 fortitude of the several usual sorts of timber, as upon 

 suggestions previous to this work, it was several times 

 experimented by the Royal Society, tho' omitted in 

 the impression, because the tryals were not complete 

 as they now thus stand in our Register. 



MARCH 23. 1663. 



The experiment of breaking several sorts of wood 

 was begun to be made : And there were taken three 

 pieces of seveial kinds ; of fir, oak, and ash, each an 

 inch thick, and two foot long, the fir weighed 8^ 

 ounces, and was broken with 200 1. weight : The 

 oak weighed 12! ounces, broken with 250 weight : 

 The ash weigh'd ioj ounces, broken with 325 weight. 



Besides there were taken 3 pieces of the same sort 

 of wood, each of J inch thick, and i foot long : The 

 fir weigh'd i ounce, and was broken with f of an i oo: 

 The oak weigh'd if ounces, broken with f of an 100 : 

 The ash weighed if ounces, broken with 100 1. 



Again, there was a piece of fir J inch square, and 

 two foot long, broken with 33 1. A piece of i inch 

 thick, i inch broad, and 7 foot long, broken with 



