What do we mean by 'Elderly'?

Far enough back that ‘billy’ was still a novel word, at least in Adelaide, one that had to be placed in quotes, this little tale appeared in a South Australian newspaper:

Lionel Lindsay, Ruins, wood engraving.

...we fell in with an elderly man who was tailing cattle. Having just boiled the “billy,” we invited him to partake of a pannican of tea, which he accepted.
— South Australian Register, 3 November 1857, 3.

The old man turned out to be an old lag, but how old was he, really? What did they mean by "elderly".

My curiosity all started with the 1931 case that shows up as the last item in the short list. I had come across that particular snippet some years ago, and for the present work I am doing on Australian English I went back, looking for that curious paragraph.

I may rate as elderly in their terms, but my search skills are still good, so I found it, Then I cast the net wider, seeking more evidence of how we thought when life expectancy was lower. 

My samples are telling. Watch the changing (and unchanging) meaning of ‘elderly’, below:

1900:

An elderly man was walking along the Port Melbourne pier, near the railway station, when he suddenly fell unconscious … and was afterward conveyed to the Melbourne Hospital by Constable Dooley. On examination in the casualty room the unfortunate man was found to be dead. The deceased was about 55 years of age…
— The Argus, 2 January 1900, 5.

1901:

A fatality occurred at Daly's Baths in the Royal Arcade to-day. This afternoon, an elderly man between 55 and 60 years of age … went to Daly's, and paid for a warm bath … efforts [were] made to resuscitate him, but without avail.
— Mount Alexander Mail (Vic) 30 July 1901, 3.

1915:

An elderly man named John Roberts died suddenly in the killing pen of John Smith, butcher, yesterday afternoon … He was 53 years of age…
— The Inverell Times, 9 February 1915, 4.

1928:

ELDERLY WOMAN INJURED. Knocked down by a motor car in Wellington-parade, near Cliveden Mansions, Teresa Evans, 53 years, of Jolimont, was yesterday admitted to Melbourne Hospit[al] suffering from a fractured skull.
— The Age, 8 May 1928, 10.

1931:

The alleged victim of the assault, an elderly woman, 46 years of age, said she resided with her husband and children at Boulder.
— Kalgoorlie Miner, 6 June 1931, 7.

So now you know what I claim to be of advanced middle age!