An essay on bread [electronic resource] : Wherein the bakers and millers are vindicated from the aspersions contained in two pamphlets; one intitled Poison detected: and the other, The nature of bread honestly and dishonestly made. Proving the impossibility of mixing lime, chalk, whiting and burnt bones in bread, without immediate discovery. With plain and easy experiments to discover alum and other admixtures in bread, instantly. To which is added, an appendix; explaining the vile practices committed in adulterating wines, cider, porter, punch, vinegar, and pickles. With easy methods to detect such abuses. By H. Jackson, chemist.