This molecular modeling set is labelled after August Wilhelm von Hofmann and signed 'Manuel Gonzalez Verdiguier Madrid' The set comprises five stands...
{"Image ImageDescription": "SPAIN - JULY 10:  This molecular modeling set is labelled after August Wilhelm von Hofmann (1818-1892) and signed 'Manuel Gonzalez, Verdiguier, Madrid'. The set comprises five stands and coloured balls with attached spokes, labelled with chemical formulae and brass collars. The carbon atoms are tetrahedral. Each ball represents an atom of a chemical element, and can be connected to other ?atoms? by means of bonds represented by inserting the connecting pegs in holes in the balls. The number of holes in a ball represents the number of molecular bonds atoms of different elements are able to form. This is determined by an element?s valency, which is dictated by the number of electrons in the outermost shell of an atom of that element.  (Photo by SSPL/Getty Images)", "Image Copyright": "SSPL/Science Museum"}