![](https://coimages.sciencemuseumgroup.org.uk/374/634/medium_thumbnail_smg00084548.jpg)
Henry Augustus Rowland 1848 - 1901
Professor at John Hopkins University, Baltimore, Maryland, United States. Physics experimentalist, he developed a way of ruling large diffraction gratings for using in optical experiments
Professor at John Hopkins University, Baltimore, Maryland, United States. Physics experimentalist, he developed a way of ruling large diffraction gratings for using in optical experiments