It shall not be lawful for any Waggon, Wain, Cart, or other Carriage so drawn or propelled as aforesaid, not having cylindrical Wheels, to carry any greater Weight than is permitted in such Waggon, Wain, Cart, or Carriage by the General Turnpike Act; and it shall not be lawful for any Waggon, Wain, Cart, or other Carriage having cylindrical Wheels to carry, over or above the Weight of the Waggon, Wain, Cart, or Carriage, any greater Weight than One Ton and a Half for each Pair of Wheels, unless the Fellies, Tires, or Shoes are Four Inches or more in Breadth; nor to carry a greater Weight than Two Tons for each Pair of Wheels, unless the Fellies, Tires, or Shoes are Six Inches or more in Breadth; nor to carry a greater Weight than Three Tons for each Pair of Wheels, unless the Fellies, Tires, or Shoes are Eight Inches or more in Breadth; and for every single Wheel One Half of that permitted to be carried on a Pair of Wheels; nor in any Case to carry a greater Weight than Four Tons on each Pair of Wheels, or Two Tons on each Wheel; but if such Waggons, Wains, or other Carriages are built and constructed with Springs upon each Axle, then they shall be allowed to carry One Sixth more Weight in addition to the above-mentioned Weights upon each Pair of Wheels : Provided always, that the Regulation of Weight herein mentioned and provided shall not extend to any Waggon, Wain, Cart, or other Carriage carrying only One Tree or One Log of Timber, or One Block of Stone, or One Cable or Rope, or One Block, Plate, Roll, or Vessel of Iron or other Metal, or compounded of any Two or more Metals cast, wrought, or united in One Piece.