Thomas Digges's father was Leonard Digges who was himself a fine mathematician who wrote on various scientific topics including surveying. Thomas received his early education from his father but, when he was fourteen years old, his father died and at that time Thomas decided that he wanted to continue his father's work. John Dee essentially seems to have stepped in to act as a father to the young Thomas who received advanced mathematical instruction from Dee. He was to remain a friend of Dee's throughout his life and undertook joint work with him.
Digges wrote on platonic solids and archimedian solids and his contributions appear in Pantometria which he finished in 1571. This work included contributions by Digges's father Leonard who had been working on it at the time of his death. The completed work contains Digges' description of how lenses could be combined to make a telescope. Although Digges and Dee were working together at this time making accurate astronomical observations there is no evidence that they actually constructed a telescope with which to observe celestial objects. We know that Digges, among other instruments used a cross-staff to determine the positions of stars, planets and comets but when a new star appeared in 1572 he used a six foot ruler which he suspended from a tree which he used to determine whether the new star moved in relation to the other stars close to in in the sky. Pantometria also contains a description of a new instrument for surveying which allowed the surveyor to draw lines of sight directly. Here is Digges' description:-
Instead of the horizontal circle, use only a plane table or board whereon a large sheet of parchment or paper may be fastened. And thereupon in a fair day to strike out all the angles of position each as they find them in the field without making computation of the degrees and fractions.
In 1573 Digges published Alae seu scalae mathematicae, a work on the position of the new star which is often called Tycho Brahe's supernova of 1572 since Brahe also observed the star and determined its position accurately. Digges' work includes observations of the position of the 'new star' and trigonometric theorems which could be used to determine the parallax of the star. The observations are particularly impressive making Digges one of the ablest observers of his time. Digges's friend Dee published a similar work on the supernova and the two works were often put in a single binding by booksellers and sold as a single volume.
The appearance to the 'new star' contradicted the standard view of the universe at that time. The observations to determine the parallax of the star made by Digges and others confirmed that the star could not be between the sphere of the moon and the Earth, and this was the only place that, acording to the views of the time, change could take place. Digges was quick to point out that this new star, which slowly began to fade from view in 1573, provided the ideal observational evidence to allow alternative theories of the universe to be considered. This was a bold statement since the Catholic Church began to view any suggestions of alternative cosmologies as heretical.
Digges became the leader of the English Copernicans and used his observations of the supernova to justify the heliocentric system. One of his ideas was that the movement of the Earth round the sun meant that the Earth moved towards and then away from the star causing it to brighten and fade. However when the brightening failed to occur periodically, this ideas was seen to be wrong.
He translated part of Copernicus's De revolutionibus and added his own ideas of an infinite universe with the stars at varying distances in an infinite space. It was his belief that the distances to the stars varied that at first seemed to be consistent with the new star being a faint one close to the Earth. Digges wrote to William Cecil, the leading statesman of the Elizabethean era, requesting support for the astronomical work he was carrying out. He makes his Copernican views very clear in this letter quoted in :-
I cannot here set a limit to again urging, exhorting and admonishing all students of celestial wisdom, with respect to how great and how hoped for an opportunity has been offered to Earyth dwellers of examining whether the monstrous system of celestial globs ... has been fully corrected nd amended by that devine Copernicus of more than human talent, or whether there still remains something else to be further considered. This, I have considered, cannot be done otherwise than through most careful observations, now of this most rare star, now of the rest of the wandering stars and through varous changes in their appearances, and all done in the various regions of this dark and obscure terrestial star, where, wandering as strangers, we lead in a short space of time, a life harrassed by various fortunes.
Digges published A Perfit Description of the Caelestial Orbes in 1576 which again restates Copernicus's views.
As well as having a military career, Digges also wrote and worked on other military matters. His book Stratioticos (1579) is a mathematics book for soldiers and contains the first discussion of ballistics in a work published in England. He also worked on fortifications, being in charge of the fortification of Dover harbour in 1582. A year earlier he had been involved in producing plans for Dover castle.
Digges was a member of parliament from 1572 and again in 1584. His military career was with the English forces in the Netherlands from 1586 to 1594. The modern state of the Netherlands came into existence with the Treaty of Utrecht in 1579. This was the year Digges wrote his military work Stratioticos which he dedicated to Robert Dudley, Earl of Leicester. Dudley was named governor-general of the Netherlands in 1586 and Dudley appointed Digges to be master-general of his army to assist him in the campaign.
Article by: J J O'Connor and E F Robertson