We will now take it for granted that the amateur is in full possession of, or can obtain, all the information necessary to enable him to distinguish between a right and a wrong date. He has still, however, to bear in mind that even a right-dated volume may be in such a wretched condition as to be hardly worth purchasing. If he will take a walk down Holywell Street he may frequently meet with genuine Elzevirs which the dealers will be only too glad to dispose of for a shilling or two each. The reason of this is that, not only are the works offered for sale _not_ "of the good date" (_i.e._, inferior editions), but they are also, in the vast majority of instances, battered, dirty, and, worse than all, "cropped," sometimes even to the very headlines. For a dirty book there is some hope, since it may be possible to clean it, but for a cropped specimen there is none: like Lucifer, it has fallen from its high estate "never to rise again". As the measurement of these small books is always made in millimetres, 25.4 of which go to the inch, the enthusiastic collector carries with him an ivory rule on which the French measures are marked. The _Ovid_ of 1629, 3 vols. 16mo, runs to 127 millimetres; the _Caesar_ of 1635 to 130 millimetres--anything below 125 millimetres is hardly worth looking at; the _Virgil_ of 1676, if uncut, reaches as high as 148 millimetres, or, if in _grand format_, even to 184 millimetres. A book of high measurement, or entirely uncut, may be worth L100 or more, according to its quality; but if cropped below the fashionable height it would not bring as many shillings. A copy of _Le Pastissier Francois_, 128 millimetres high, was not long ago offered at 1500 francs, or L60; an entirely uncut copy brought 10,000 francs, or L400; and yet between the two there could not have been a greater difference in height than three, or at the most four, millimetres. The truth is that Elzevirs are measured with the same accuracy observable in the weighing of precious stones, and the 25th part of an inch makes a wonderful difference. That book collectors sometimes go to extreme lengths cannot be doubted by anyone who has spent much time in their company; but the English bibliophiles are not to be compared in this respect with their French brethren. The latter are _the_ collectors of Elzevirs, and will frequently spend enormous sums on specimens which from their appearance and real practical utility are worth hardly anything at all. What can be more incorrect than the Leyden _Virgil_ of 1636? It is literally crammed with the most shameful errors, so much so that Heyne says it is destitute of the slightest trace of any good quality. Yet the famous Charles Nodier spent nearly all his life searching for a genuine copy of the first edition, which, when obtained, filled a place purposely left vacant for it. Up to that time he had declined to "profane" his shelves with any _Virgil_ at all.