Many ancient works, such as the Bible and the Greek tragedies,[citation needed] survive in hundreds of copies, and the relationship of each copy to the original may be unclear. Textual scholars have debated for centuries which sources are most closely derived from the original, hence which readings in those sources are correct.[citation needed] Although biblical books that are letters, like Greek plays, presumably had one original, the question of whether some biblical books, like the Gospels, ever had just one original has been discussed. Interest in applying textual criticism to the Qur'an has also developed after the discovery of the Sana'a manuscripts in 1972, which possibly date back to the 7–8th centuries.
Why are scholars concerned with analysis of the Gospels over the letters?
biblical books that are letters, like Greek plays, presumably had one original

Two common considerations have the Latin names lectio brevior (shorter reading) and lectio difficilior (more difficult reading). The first is the general observation that scribes tended to add words, for clarification or out of habit, more often than they removed them. The second, lectio difficilior potior (the harder reading is stronger), recognizes the tendency for harmonization—resolving apparent inconsistencies in the text. Applying this principle leads to taking the more difficult (unharmonized) reading as being more likely to be the original. Such cases also include scribes simplifying and smoothing texts they did not fully understand.
Is a lectio brevrio or lectio difficilior approach more akin to the original text?
Applying this principle leads to taking the more difficult (unharmonized) reading as being more likely to be the original.

The usefulness of the canals was short-lived, though some have now been restored for recreation. The 19th century also saw the construction of railways to and through Somerset. The county was served by five pre-1923 Grouping railway companies: the Great Western Railway (GWR); a branch of the Midland Railway (MR) to Bath Green Park (and another one to Bristol); the Somerset and Dorset Joint Railway, and the London and South Western Railway (L&SWR). The former main lines of the GWR are still in use today, although many of its branch lines were scrapped under the notorious Beeching Axe. The former lines of the Somerset and Dorset Joint Railway closed completely, as has the branch of the Midland Railway to Bath Green Park (and to Bristol St Philips); however, the L&SWR survived as a part of the present West of England Main Line. None of these lines, in Somerset, are electrified. Two branch lines, the West and East Somerset Railways, were rescued and transferred back to private ownership as "heritage" lines. The fifth railway was a short-lived light railway, the Weston, Clevedon and Portishead Light Railway. The West Somerset Mineral Railway carried the iron ore from the Brendon Hills to Watchet.
What was built int the 19th century
19th century also saw the construction of railways to and through Somerset