It must next be considered what amount of reliance can be placed upon the Irish annals and annalists, who have preserved to us our early history. If, in those few cases where we happen to have some credible external evidences of early events, we find our native annalists notoriously at variance with such evidences, our faith in them must of necessity be shaken. If, on the other hand, we find them to coincide fairly well with these other accounts taken from foreign sources, we shall be inclined to place all the more reliance on their accuracy when they record events upon which no such sidelights can be thrown. Now, from the nature of the case, it is exceedingly difficult, considering how isolated Ireland was while evolving her own civilisation, and considering how little in early ages her internal affairs clashed with those of Europe, to find any specific events of which we have early external evidence. We can, for instance, apart from our own annals and poems, procure no corroborative evidence of the division of Ireland between Conn and Owen, of the destruction of Emania by the Three Collas, or of the battle of Gabhra. But despite the silence upon Irish affairs of ancient foreign writers, we have luckily another class of proof of the highest possible value, brought to light by the discoveries of modern science, and powerfully strengthening the credibility of our annals. This is nothing less than the record of natural phenomena. If we find, on calculating backwards, as modern science has enabled us to do, that such events as the appearance of comets or the occurrence of eclipses are recorded to the day and hour by the annalists, we can know with something like certainty that these phenomena _were recorded at the time of their appearance by writers who observed them_, whose writings must have been actually consulted and seen by those later annalists, whose books we now possess. Nobody could think of saying of natural phenomena thus accurately recorded, as they might of mere historical narratives, that they were handed down by tradition only, and reduced to writing for the first time many centuries later. Now it so happens that the Annals of Ulster, annals which treat of Ireland and Irish history from about the year 444, but of which the written copy dates only from the fifteenth century, contain from the year 496 to 884, as many as 18 records of eclipses and comets which agree exactly even to the day and hour with the calculations of modern astronomers. How impossible it is to keep such records unless written memoranda are made of them by eye-witnesses, is shown by the fact that Bede, born himself in 675, in recording the great solar eclipse which took place only eleven years before his own birth is yet two days astray in his date; while, on the other hand, the Ulster annals give not only the correct day but the correct hour--thus showing that Cathal Maguire, their compiler, had access either to the