Marey type sphygmograph, with Mahomed type modification, in case, by J Weiss and Son, 62 Strand, London, England, 1875-1885

A sphygmograph was used to measure the strength and rate of a person's pulse. In 1863, Étienne-Jules Marey (1830–1904), a French scientist, made the device portable. Placed on the wrist, allowing the pulse to be magnified and easier to record. Almost a decade later, Frederick Akbar Mahomed made a further modification so arterial blood pressure could also be measured. Mahomed was the first in Britain to recognize that high blood pressure was a primary condition of kidney damage.