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see protactiniumprotactinium
, radioactive chemical element; symbol Pa; at. no. 91; mass number of most stable isotope 231; m.p. greater than 1,600°C;; b.p. 4,026°C;; sp. gr. 15.37 (calculated); valence +4, +5. Protactinium is a malleable, shiny silver-gray radioactive metal.
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Among the law publications in this inventory were Littleton's Tenures, 400 copies of Natura Brevium in English, 500 in French, plus "centum and quinquaginta alios libros de natura brevium [one hundred and fifty other books of Natura Brevium].
The following are the books, other than Littleton's Tenures, Natura Brevium, and the yearbooks, published by both Smyth and Middleton.
7, Middleton-STC 15733); Natura Brevium (Smyth-STC 18397, Middleton-STC 18396 [1545?