In the second era (7th–9th editions, 1827–1901), the "Britannica" was owned by the Edinburgh company, A & C Black. Although some of the people who helped write the "Britannica" helped because they were friends of the most important editors, many other people wanted to help the "Britannica" because it was becoming very successful. These people came from many other countries, and some of them were very famous for the things they wrote about. An index of all the articles was written to add to the 7th edition of the encyclopaedia, and they continued to make an index until 1974. The first English chief editor was Thomas Spencer Baynes, who led the making of the famous 9th edition, which is also called the "Scholar's Edition". The 9th edition is considered to be the "Britannica" most meant for students ever written. However, at the end of the 19th century, the 9th edition was already too old and the "Britannica" had many financial problems.