Boxed made by Hawksley Crista, London. British neurologist William Gowers (1845-1915) invented the haemoglobinometer in 1875. It rapidly tested the amount of haemoglobin in blood by comparing its colour with a reference tube. Haemoglobin is the part of the blood responsible for carrying oxygen around the body. It is essential for a healthy diet. The Sahli haemoglobinometer was devised by Hermann Sahli (1856-1933). It was made by Hawksley and Sons Limited in London.