A Salty Dog is essentially a Greyhound with the addition of salt on the rim of the glass.  They are perfect for a hot, hot day.

For each serving you will need:

Salt

Crushed ice

1 ½ ounces (jigger or shot) of Gin or Vodka

5 or 6 ounces of grapefruit juice

Moisten the rim of a tall glass with grapefruit juice and then coat the rim with salt.  Fill the glass with crushed ice.  Pour in the Gin or Vodka and the grapefruit juice.  Stir gently and serve with a straw and a slice of lime.