I've just found an excellent website which allows easy reading of the above book in pdf format, apologies if it's already been mentioned on this site, I couldn't find it when searching. This highly informative illustrated book will hopefully be of interest to anyone researching ancestors working in the County's manufactories, workshops & mills around the start of the 20th century.

From the website introduction page

" This 82 page document was compiled, published and printed in 1904 by Chance and Bland, the publishers of the Gloucester Journal. It provides a brief history and the current situation for 100 Gloucestershire firms, These range from W Sutton Gardner of Cheltenham, artificial teeth manufacturers ("the oldest business of the kind in the county") to the huge Gloucester Railway Carriage and Wagon Works Co. Ltd. ("Gloucestershire's largest company").

In the preface to the book, the publishers refer to the wealth of literature on the history, geology, archaeology, churches and scenic beauty of Gloucestershire while little had published on the County's industries and the “resourcefulness and adaptability of its people”. The book is a attempt at redressing the balance. The preface is worth reading for an interesting view of the state of industry and commerce in the County at the close of the Victorian era!

It is not known who wrote the articles but it seems likely it was the publisher's own journalists. Although the accounts may appear to give a favourable bias towards the firms, they nevertheless provide valuable information. Indeed in some instances they may be the only surviving sources for firms that have long since disappeared. However, there are some notable omissions, such as the Gloucester engineering firm, Fielding and Platt."

https://coaley.net/indglos-1904-index/

Companies with a direct Forest link include:
Wintle's brewery, Mitcheldean
https://coaley.net/sites/files/indglos_1904/ig190456.pdf

Lydbrook Chemical Company
https://coaley.net/sites/files/indglos_1904/ig190458.pdf

James Constance & Sons, woodturners, Longhope
http://www.coaley.net/indglos_1904/ig190440.pdf

Among many other North Gloucestershire companies may be found:
Foster Bros, Oil & Cake Mills
https://coaley.net/sites/files/indglos_1904/ig190451.pdf

and no relation, but intriguingly named;
John Milton Jones and Co, 'Jones's Specialities' (Gloucester) ..??!!
https://coaley.net/sites/files/indglos_1904/ig190466.pdf

I do hope this excellent website gives as much pleasure to you as it has to me.
J Jones...