Spark discharge figure
                                Date
                            
                            
                                1892
                            
                            
                        
                            
                            
                            
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                                Material
                            
                            
                            
                        
                            
                            
                            
                                Dimensions
                            
                            
                                height (drawing): 133mm
width (drawing): 126mm
                            
                        
                            
                            
                            width (drawing): 126mm
                                Subject
                            
                            
                            
                        
                            
                            
                            
                                Description
                            
                            
                                Diagram created by sparking from Lord Armstrong’s machine for producing high tension electricity. These patterns were made in a powder of magnesium oxide (‘calcined magnesia’) and carbon black. The images were then photographed and drawings produced from them. 
The author states in his paper that: ‘No.17 shows similar effects [to No.16] produced by heavier discharges on a more thickly covered dust plate…’.
Illustration from the manuscript version of the paper ‘On a multiple induction machine for producing high tension electricity, and on some remarkable results obtained with it’, by Lord Armstrong, Proceedings of the Royal Society, vol.52 (1892), pp.176-191. Printed as figure 17 plate 11 in the published paper.
The image is inscribed below in ink: ‘No.XVII’ and ‘4/7’. Imprint details verso.
William George Armstrong, Baron Armstrong (1810-1900) armaments manufacturer and industrialist was elected a Fellow of the Royal Society in 1846.
                            
                            
                        
                            
                            
                            The author states in his paper that: ‘No.17 shows similar effects [to No.16] produced by heavier discharges on a more thickly covered dust plate…’.
Illustration from the manuscript version of the paper ‘On a multiple induction machine for producing high tension electricity, and on some remarkable results obtained with it’, by Lord Armstrong, Proceedings of the Royal Society, vol.52 (1892), pp.176-191. Printed as figure 17 plate 11 in the published paper.
The image is inscribed below in ink: ‘No.XVII’ and ‘4/7’. Imprint details verso.
William George Armstrong, Baron Armstrong (1810-1900) armaments manufacturer and industrialist was elected a Fellow of the Royal Society in 1846.
                                Associated place