(Due to arrive Canberra 29.3.29)
My dear P.M.,
Your memorandum of 18th January re the classifying and numbering of my letters.  I regret that I am unable to deal with this properly by this mail. However, I will do as you suggest and will start new and separate number series for 'Confidential' letters (which can go from you to the External Affairs Department for perusal and filing) and the 'Personal and Confidential' letters (for your own eye). As far as concerns the letters that you now have, all 'Confidential' letters can go to the External Affairs Department but none of the 'Personal and Confidential'.
I will send you a list of the new numbers to be given to 'Confidential' letters now in your possession.
I am segregating here all telegrams that do not concern the files and will advise you by next mail or by telegram of cables in your possession that should not go on the official files.
You can take it that no telegram in Cypher 'M' between you personally and myself should go on official files, and I will maintain separate files of them here.
I am, Yours sincerely, R.G. CASEY