Nigidius vied with Varro in multifarious erudition, and the number of his works—grammar, criticism, natural history, and the origin of man, having successively employed his pen. His writings are praised by Cicero, Pliny, Aulus Gellius, and Macrobius; but they were rendered almost entirely unfit for popular use by their subtlety, mysteriousness, and obscurity(102)—defects to which his cultivation of judicial astrology, and adoption of the Pythagorean philosophy, may have materially contributed. Aulus Gellius gives many examples of the obscurity, or rather unintelligibility, of his grammatical writings(103). His chief work was his Grammatical Commentaries, in thirty books, in which he attempted to show, that names and words were fixed not by accidental application, but by a certain power and order of nature. One of his examples, of terms being rather natural than arbitrary, was taken from the word _Vos_, in pronouncing which, he observed, that we use a certain motion of the mouth, agreeing with what the word itself expresses: We protrude, by degrees, the tips of our lips, and thrust forward our breath and mind towards those with whom we are engaged in conversation. On the other hand, when we say _nos_, we do not pronounce it with a broad and expanded blast of the voice, nor with projecting lips, but we restrain our breath and lips, as it were, within ourselves. The like natural signs accompany the utterance of the words _tu_ and _ego_—_tibi_ and _mihi_(104). Nigidius also wrote works, entitled _De Animalibus_, _De Ventis_, _De Extis_, and a great many treatises on the nature of the gods. All these have long since perished, except a very few fragments, which have been collected and explained by Janus Rutgersius, in the third book of his _Variæ Lectiones_, published at Leyden in 1618; 4to. In this collection he has also inserted a Greek translation of another lost work of Nigidius, on the presages to be drawn from thunder. The original Latin is said to have been taken from books which bore the name of the Etruscan Tages, the supposed founder of the science of divination. The Greek version was executed by Laurentius, a philosopher of the age of Justinian, and his translation was discovered by Meursius, about the beginning of the seventeenth century, in the Palatine library. It is a sort of Almanack, containing presages of thunder for each particular day of the year, and beginning with June. If it thunder on the 13th of June, the life or fortunes of some great person are menaced—if on the 19th of July, war is announced—if on the 5th of August, it is indicated that those women, with whom we have any concern, will become somewhat more reasonable than they have hitherto proved(105).