Background to the site
The site was originally bounded to the North by Leith Sands - where the famous Leith Races were held at low tide until 1816, The image to the left is from the City archive. The site lay just to the right of the beehive shaped kilns of the glass works.
The image below (by Walter Geikie) , also from the City Archive, gives a more distant view of the sands from the east.
The Origins of Coal Gas
Gas was first produced from coal in 1792 by William Murdoch, a native of Cumnock in Ayrshire who at the time was working for Boulton & Watt in England. Within a few years, Boulton & Watt were selling entire gas lighting systems to cotton mills, where the combination of lighting by candles and oil from the cotton had led to many fires.
The idea of a public gas supply came from a German, Fredericht Albrecht Winzer, who in 1812 formed the Chartered Gas Light and Coke Company in London.
The first gas was distributed to people in Edinburgh in 1818 by the Edinburgh Gas Light Company when the gas works on New Street was established in the city just off the Canongate. The Leith Gas Light Company was later formed in 1823, with construction on the gas works site on Baltic Street, Leith, starting in circa 1835.
Coal Gas in Leith
At the time of its construction, the gas works was located along the coast of the Firth of Forth just to the east of the mouth of the Water of Leith. A branch of the Edinburgh and Dalkeith Railway was built in circa 1835 to the north of the site, in the small area of land between the site and the coast.
The construction of the railway line was essential for the operation of the gas works as it required large amounts of coal to be brought into the site, which at the time was only possible by railway.
The basic process for making gas from coal used in the early 19th century remained essentially unchanged right through until the last coal gas works closed in the 1970s.
Coal in a closed tube called a retort was heated in a furnace. The gasses given oﬀ – mainly hydrogen and carbon monoxide – passed through a water trap (“hydraulic main”)
The gases were then cooled in a condenser, where tar and some other liquids were removed.
The gas then passed through a purifer to remove sulphur compounds and other impurities.
The gas was then either used or stored in a gas holder. Later in the 19th century, steam driven exhausters were introduced to pump the gas through the gas works and into the mains system
Working in the gas industry was hard and often dangerous. The retorts had to be filled or ‘charged’ with coal by hand which was tough, back-breaking work. Although larger gas works introduced mechanical charging and vertical or inclined retorts from the late -nineteenth century, hand charging continued at smaller gas works until the 1960s.
The waste products produced by the gas industry such as coal tar, foul lime and spent oxide contaminated the sites of former gas works. Public concern about the level of pollution and the quality of the gas culminated in a raft of legislation which sought to regulate the financial accountability and environmental impact of Victorian gas companies.
7-27 Constitution Street
At the turn of the 19th century, Baltic Street and Constitution Road (later Constitution Street) had already been laid out as two of the earliest established streets in Leith, as shown on Aitchison’s Plan of 1794.
The first known use of 7-27 Constitution Street (from at least 1802) was as a Naval Yard. However with the opening of a branch of the Edinburgh and Dalkeith Railway in 1835 the site became a coal depot and granary.
The principal buildings (along with the railway station) survived into the 1970s before being demolished, with the site becoming a scrap yard.