Scientijlc TnielUyence — Aris^ ^c^ 209 



t>ther3 interested in tlie making or maintaining of streets. We will, 

 therefore, here give a short account of them : — 



\9ty It is found that what is technically called ruble causewaying, 

 although cheapest at first, is the most unprofitable description of mate- 

 rial which can be laid where the thoroughfare is great. 



2rf, The common description of dressed causewaying is equally in- 

 effective. 



3</, Macadamised streets in towns, where the thoroughfare is great, 

 are exceedingly unprofitable, and much more expensive to keep up 

 than any other description of street. 



4///, Whinstone (Trap) is a chalk compared to the granite (Por- 

 phyry) from Inverary Quarry. This was proved by the Trustees in 

 Jamaica ^Street. Both descriptions of material were subjected for 

 three years to an equal amount of tear and wear. On minute in- 

 spection, the whin was found worn down from 2 J to ?* inches, while 

 the granite was so little defaced, that the marks of the tools used in 

 preparing it were still visible. 



.')///, To make good paving, the material must consist of well-made 

 square-dressed blocks, all of an equal depth, and must be free of holes 

 and bumps on the tops and bottoms, and be carefully laid on a bed of 

 sharp river sand, the stratum on which it is laid being previously pre- 

 pared to the exact curvature required, or surface of the street in its 

 finished state. The stones, being nearly smooth on the top, allow the 

 carts to roll along, instead of bumping on the stones, which causes 

 immediate destruction to the street. 



6?//, The Inverary granite is considered to be the most economical 

 description of material which can be adopted, as, from its extraordi- 

 nary durability, a street, when laid with it on the improved system, is 

 calculated to last at least for fifty years. 



The Commissioners of Police are about to have the High Street 

 paved with this durable material. They and their superintendent of 

 streets deserve the greatest credit for the great interest they bestow on 

 the paving department 



18. Eastern Method of Measuring Time. — The people of the East 

 measure time by the length of their shadovv'. Hence, if you ask a 

 man what o'clock it is, he immediately goes into the sun, stands erect, 

 then looking where his shadow terminates, he measures his length with 

 his feet, and tells you nearly the time. Thus the workmen earnestly 

 desire the shadow which indicates the time for leaving their work. 

 A person wishing to leave his toil says, " How long my shadow is in 



VOL. XXXIII. NO. LXV. JULY 1842. o 



