Weak analogy

Conclusion depends on defective analogy

The flow of electricity through a wire is similar to the flow of water through a pipe. Obviously a large diameter pipe will carry a larger volume of water than a pipe of small diameter. Therefore, a large diameter wire should carry a greater flow than a small diameter wire.

All right-thinking people will support the Board of Education's decision to destroy novels in the school libraries that are offensive to the moral standards of the community. If there were an epidemic of typhoid, the health authorities would be expected to intervene immediately to protect our children.