does postassium nitrate have a high or slow conductivity

As a crystal, very low.

In solution, I say high conductance, however it is about half as much as solutions of sodium or potassium chloride.

See table 73 in section 81 of this book
http://books.google.com/books?id=ItbQAAAAMAAJ&pg=PA198&lpg=PA198&dq=potassium+nitrate+solution+conductivity&source=bl&ots=sQjXaRYjxI&sig=U7RQLbG5uN2SGj2EE7D2mHyu9UU&hl=en&ei=JSdNS86SN5TKlAfU8PHFAQ&sa=X&oi=book_result&ct=result&resnum=7&ved=0CCgQ6AEwBjgK#v=onepage&q=potassium%20nitrate%20solution%20conductivity&f=false

The melt also has a high conductance.

To determine the conductivity of potassium nitrate, we need to consider its properties as an ionic compound.

Potassium nitrate (KNO3) is a soluble salt that dissociates into its constituent ions, potassium (K+) and nitrate (NO3-) ions, when dissolved in water. Since these ions are free to move and carry electric charge, the conductivity of potassium nitrate can be studied.

In general, ionic compounds have relatively high conductivity when dissolved in water because of the presence of freely moving charged ions. This makes them good conductors of electricity. However, the specific conductivity of potassium nitrate will depend on various factors, such as concentration and temperature.

If you need precise conductivity values for potassium nitrate, you can refer to scientific literature or conduct experiments using conductivity meters. These devices measure the electrical conductivity of a solution and provide specific values for different substances, including potassium nitrate.

In summary, potassium nitrate can be expected to exhibit relatively high conductivity when dissolved in water due to the mobility of its constituent ions. However, for precise conductivity values, additional research or experimentation is needed.