Which is safer the Velocipede or the Mountain Bike?

And Why???
Thank you!!!

And which is the fastest out of the two.

Velocipede is a name that refers to any wheeled foot powered machine. The modern mountain bike could also be described as a type of velocipede.
http://www.merriam-webster.com/dictionar...

Assuming that you are refering to one of the many types of bicycle that were made in the 1800's to early 1900's then.
Most of these where quite primative, brakes were basic to non-exsistant. Most where very slow and difficult to do a major injury on. The exception would be the high wheelers (Penny farthings). They are pretty quick on hard flat surfaces, and there is some way to fall. The first diamond frame bikes were known as "safety bicycles" which should give a hint to the high wheeler's reputation.

The modern mountain bike handles quite well. it is quite refined and brakes exceptionally well. On the down side they are capable of quite high speed and are used on trails lined with trees and large rocks. There is a relatively high chance of serious injury if you come off the trail at high speed and hit something.

The most dangerous part on any bicycle is the rider. So I'm going with the mountain bike being more dangerous, but only because it gives more opportunity for a dangerous rider to injure themself. Kind of like people don't get killed as much on really bad roads,only because they can't get enough speed up to do the damage.

Modern mountain bikes are usually faster on most terrain. A high wheeler might give them a run for the money on a hard flat surface.