The number of cards in this series is not known for sure.  There are 19 cards illustrated here. Michael Simco in his booklet "The Semi-official postcards of Tasmania"  lists another three:

• Mount Lyell railway: Mt Lyell Company’s wharves
• Tasmanian gold mine, Beaconsfield
• Loading potatoes at Devonport

There is variation in the colour of the cards; some have a bluish tint and some have a brownish tint.  It has been claimed that these were from two printings, but I do not have enough cards available to confirm that.