 On 12 August 1914 , Weir received a telegram from Colonel <unk> Sinclair @-@ Maclagan , the designated commander of the 3rd Brigade , offering him the command of the 10th Battalion . Weir promptly accepted , and on 17 August was appointed as a lieutenant colonel in the Australian Imperial Force ( AIF ) , making him the first South Australian to be commissioned in the AIF . He retained his rank of colonel in the part @-@ time forces in an honorary capacity . 
