Information from now dead web page. www.bygonetimes.com/the-history-of-celestion.html
In 1924 Cyril French set up 'The Electrical Manufacturing and Plating Co' at 29 High Street, Hampton Wick, London. Helping Eric Mackintosh to perfect his cone loudspeaker design, they soon began manufacturing them aided by Cyril's brother Ralph French.
The Celestion loud speaker was launched early in 1925 by The Electrical Manufacturing and Plating Co at a retail price of 6 pounds, ten shillings, with a choice of oak, walnut or mahogany cabinet. It was sold as ‘The Loud Speaker of Distinction’ and was favourably reviewed by 'Popular Wireless' as "a high-class instrument capable of high-class perfomances".
In 1927 The Celestion Radio Co and Celestion Ltd were formed; it made Celestion loudspeakers and Celestion Woodroffe gramophone pickups. Loudspeaker models included the C10, C12, C14, and C24. All very favourably reviewed by Popular Wireless. The company's motto, and for many years to follow, was "The Very Soul of Music". Through the late 1920's Celestion enjoyed a burgeoning trade, and in 1929 moved to larger scale premises at 145 London Road, Kingston-upon-Thames.
This is my example of this speaker. Of note is the construction method of the speaker cone. The cone appears to be a very thin paper that is reinforced on both sides with two configurations of approximately 1mm square bamboo rod.
On the front side, the bamboo is formed into a spiral of 9 turns. On the back side, the bamboo is arranged in 18 radials.