Reading between the lines, it sounds as if bottle-conditioned beers were always dry hopped. Non-deposit beers, as we learned last time, didn't hang around the brewery for long. They were stored for such a short length of time, they had little chance to have any effect.
"Mr, W. Scott said that the author had not dealt with the question of the dry hopping in tank of non-deposit beers. In his (the speaker's) opinion full value was not obtained from dry hopping, as when the hops were placed in the conditioning tanks loose for a limited period they simply floated on the surface, and when caged up, with a view of subsequent use in the copper, they swelled to such an extent that very little benefit was derived by the beer."
Journal of the Institute of Brewing, Volume 20, Issue 6, November-December 1914, page 528.
This seems an ingenious way around the problem of dry-hopping effectively in a short space of time.
"With regard to dry hopping, the members might remember that seven years ago he read a paper before the section, in which he gave a diagram illustrating a very effective method of dry hopping these non-deposit beers in the tank, by suspending the hops in a bag in the tank and circulating the beer through them by means of a perforated pipe which was placed in the centre of the bag, and was suitably connected to the pump outside. That system he had employed for the past 12 years with perfect success."
Journal of the Institute of Brewing, Volume 20, Issue 6, November-December 1914, page 529.
Here's Arthur Hadley's position:
"As to his practice with regard to dry hopping, they started some years ago dry hopping in the tanks, at the rate of half a pound per barrel. He found there was very little coming from the hop. He began to reduce it, and ended by reducing it entirely, and wiping it out, and for the last two years not a dry hop had gone into the beer. They had saved hundreds of pounds thereby, and he did not think anyone could tell the difference. The amount entering the beer was so infinitesimal that it was not of the slightest use, and there was really not the slightest need for it."
Journal of the Institute of Brewing, Volume 20, Issue 6, November-December 1914, page 532.
A waste of time, basically. Half a pound per barrel is quite a lot. Whitbread's X Ale, had about 1.25 lbs of copper hops in 1914. FA, their low-gravity bottled Pale Ale, about 2 pounds*.
It's another confirmation, in a way, that flavour wasn't the top priority of bottled beer drinkers.
* Whitbread brewing record held at the London Metropolitan Archives, document number LMA/4453/D/01/079.