The price at which competition demands those lenses shall be rendered, operates against the wearer of spectacles; for the producer cannot afford to throw aside such as are faulty, and the wholesale agent and retail dispenser cannot expect to have, at the low price charged, lenses which will bear a critical examination; and thus all which can possibly be used are thrust into frames of one kind or other, from the common iron or horn sold by the poor hawkers at sixpence, eightpence, and one shilling per pair, to the more expensive frames; while many faulty glasses, after being dubbed with some ear-tickling appellation, and imbibing extraordinary “light-modifying and refractive virtues,” by passing into the hands of the hawker of a higher class, are palmed upon the unfortunate spectacle-purchasers who are simple enough to give credence to the wondrous tale. Women and children are chiefly employed to cut and edge those cheap glasses to the spectacle-frames; and who can expect they should do them better for the price? And if one glass should be unequally thick, like a wedge, while its companion in the same spectacles is miserably thin; or if the centres, instead of being equidistant from all parts of the rim are nipped into a corner; how _can_ you feel surprised when you consider that for them to earn a living, it is necessary they should finish several dozen pairs per day, and therefore, expedition, rather than excellence, is the point at which they aim? In many departments, where machinery has supplanted manual labour, the work produced is of a superior character, and will bear more critical examination; but the contrary is the fact in the case of machine-worked optical glasses, and is more especially apparent in such as are intended for microscopic and achromatic purposes. It cannot be denied that, for all such uses, lenses worked by hand, with the ordinary care of a skilful workman, as much excel those produced by machinery, as the accurate and scientific touch of the artist eclipses the random splash of the plasterer.