Wow! It's so interesting to research old newspapers from the British Newspaper Archive: https://www.britishnewspaperarchive.co.uk/
If you are browsing through old newspapers, you can find columns about candles from 12th of November 1711, in the "Newcastle Courant".
An advertisement about coloured candles was offered in "The Skegness Standard", 11th of December 1929: "having artistic candles to tone perfectly with your furnishings".
An advertisement at "The Italian Warehouse" in "The Coleraine Chronicle" from 23rd of April, 1864" offered candles from different raw materials: "Real Wax Candles, Paraffin Candles, Real Sperm Candles, Composite Candles".
A small summary of research "Arsenic in Candles" was published in "Carlisle Patriot" on 7th of April 1838: The Medico-Botanical Society carried out research for the Westminster Medical Society about the injurious effect of arsenic, which most of the factories used to produce candles for general public to gain more profit. In this article, they state that there has been experiments involving animals and birds: "During the week that these experiments were pursued, seven birds which has been exposed to the vapor of arsenical candles died, whilst the birds in the boxes where pure candles had been burning were as gay, and eat and drank as freely, at the end of the week as they did at its commencement". We should be so thankful that science back then was already looking after our healthy society and still do it to this day to help us understand how important it is to take care of our environment and the materials we use to produce our products.