TWO:(1.) Into what classes can gearing be divided?(2.) What determines the wearing capacity of gearing?(3.) What is the advantage gained by employing wooden cogs for gear wheels?(4.) Why are tangent or worm wheels not durable?You said we couldnt get away to tell anybody anyway, Sandy said, but he was compelled to admit to himself that although anyone might write such a lettereven Jeff!the postmark was Los Angeles and the enclosure had every appearance of sincerity.