The Soundex is a coded surname index based on the way a surname sounds, rather than on the way it is spelled. Surnames that sound similar, even though they are spelled differently, are all filed together. That way, even if the name was misspelled on the census, you shouldn't have any trouble finding it. To search for a particular surname, you must first work out it's code.
Every code consists of a letter followed by three numbers.
The letter is always the first letter of the surname. The numbers are assigned according to the Soundex Coding Guide below. Here are the basic steps for Soundex coding a surname. On line 1, write the surname you are coding. After it, write the numbers, found on the Soundex Coding Guide, that represent the next 3 unslashed letters in the name.