Born in Old, Northamptonshire, Slare was the son of Frederick Schloer, the German rector there, and Anna, daughter of Ralph Malory of Shelton; Theodore Haak was a cousin of his father.
[2] Introduced by Robert Hooke to the Royal Society on 3 July 1679 to show experiments on spermatozoa, then recently discovered by Leeuwenhoek, Slare was recommended for election by Haak.
[13] Hoare, Slare and Francis Lee were leaders in the charity school movement in England, and also in close touch with August Hermann Francke and the Pietists.
He was buried in the cemetery adjoining Greenwich churchyard, where an inscription on his gravestone read "Societatis de promovendo Evangelium in partibus transmarinis socius".
[3] Slare for some years regularly attended at the meetings of the Royal Society, to which he showed experiments on phosphorus, one of which he repeated after dinner at the house of Samuel Pepys.
[16] Slare continued to represent the experimentalist tradition in the Royal Society, with Patrick Blair and James Douglas, when the Newtonian and mathematical tendency became more dominant.
[18] With others (Thomas Henshaw, Hooke, Christopher Wren) Slare worked over the findings of Willem ten Rhijne in Asian medicine, after they had been presented to the Royal Society by Haak in 1682.
[20] He did translation work for the De Historia Piscium of 1686, of manuscripts of the naturalist Leonhard Baldner, for John Ray and Francis Willughby.
[21] In the case of a work the Royal Society was sent in 1684, by Johann Kunckel, Slare played the role of extracting some experimental content, to Boyle's eventual satisfaction.
He repeated experiments of Robert Boyle with ammoniacal copper salt solutions, in which air was absorbed, with an accompanying change of colour.
[24] At the request of Sir John Hoskyns, Slare examined in 1713 a number of calculi, which he showed, against a view then common, to be unlike tartar chemically.
The book was translated into German in 1718 by Georg Ludwig Piderit,[32] and annotated by Johann Philipp Seipp, with criticism of Slare's views.