The Cylinders were the transports used by the Martians to reach Earth. From Mars, the cylinders were fired at Earth and reached it in ten Earth months. In all, ten cylinders were fired in the 1902 invasion. No reason for why the shots ceased after just ten were ever given, but three theories have been forwarded:
1. The exhaust gasses from the gun/magnetic accelerator on Mars greatly polluted its atmosphere, causing greater-than-expected inconvenience.
2. The gun/hydrogen accelerator itself was badly damaged and rendered unusable.
3. The first ten were a reconnaissance team, and that if they didn't report back the invasion was called off.
Each cylinder could hold five Martians, three or four bipedal martian creatures which served as provisions, five semi-disassembled Tripods, two semi-disassembled Handling Machines, and the materials to build one Flying Machine. The diameter of each cylinder is approximately thirty yards.
Note: Wells' description of the projectile as a 'cylinder' is based upon observations of the uncovered portion. It is almost certain that the forward portion is tapered, so a more apt description of the projectile would be that of a 'giant bullet'.
The external encrustation of the projectile's outer hull is an ablative material designed to radiate heat from the atmospheric entry away from the interior. The metal used in the construction of the projectile is 'an unfamiliar alloy with a yellowish hue'. In addition, the interior of the projectile was lined with metal bars and other components that served to strengthen the hull.
The following were the landing sites in Surrey, the ten Martian Cylinders as described in Wells' novel:
1. Horsell Common
2. Addlestone Golf Links
4. Bushey Park
7. Primrose Hill