Please correct me on this, I may be wrong again, but I believe all the ledgers containing info for serial numbers 21,354 (Dec, 1891) to 24,999 (May, 1910) are not available (roughly 3645 units over 18.5 years or 197 units per year). Doing some math (assuming constant production) makes 23102 circa 1900.
I just made up this way of finding the year for the missing ledger years... there is probably a more official way:
(Serial - 21355) divided by 197 plus 1892 = circa year (The John Method)
((23102 - 21,355) / 197) + 1892 = 1900
As a test:
21,353 - 21,355 / 197 + 1892 = 1891.9
Serial number 21,353 is Dec, 1891
25001 - 21,355 / 197 + 1892 = 1910.5
Serial number 25,001 is May, 1910
Date also lines up with "Her Majesty" on the logo as King Edward started his reign in Jan, 1901.
"No. 5" is most likely the model number but I'm not knowledgable enough to know all the features. I keep hoping Chris Algar will write all the vast knowledge in his head down on paper one day.
You can look the model numbers up along with short descriptions in the old price lists available online :http://www.concertin...tstone-english/
The two closest price lists are 1859 and 1915 so a bit off from 1900 but it should be a bit of help to you anyway.
Edited by 4to5to6, 10 July 2015 - 11:31 PM.