Commonly referred to as the Pike Index, the Index to Emigrant Labourers Applying for a Free Passage to South Australia was compiled by Douglas Pike.
It was copied from records held in the Public Record Office (now National Archives) in England. It is arranged alphabetically by the name of the applicant and gives age and occupation of the person applying. It will often give the address of the applicant and records the sex and the ages of anyone accompanying them. It will not supply the names of wives or children of the applicant.
Not everybody who applied came to South Australia under the scheme. If there is an embarkation number on the application then you know that they did come.
Pat Button, a South Australian author, wrote a book called A Free Passage to Paradise? Passenger lists of United Kingdom emigrants who applied for a free passage to South Australia 1836 - 1840. Using the embarkation numbers Pat Button was able to work out which ship that people arrived on and this information is contained in the book. Sometimes when there is not a passenger list available you can find out which ship a person arrived on and what date by consulting the book.