Question.  You can now make dolls’ eyes?  Answer.  I can.  As it was eighteen years ago that I received the order I have mentioned, and feeling doubtful of my own recollection, though very strong, and suspecting that it could [not] have been to the amount stated, I last night took the present very reduced price of that article (less than half now of what it was then), and calculating that every child in this country not using a doll till two years old, and throwing it aside at seven, and having a new one annually, I satisfied myself that the eyes alone would produce a circulation of a great many thousand pounds.  I mention this merely to shew the importance of trifles; and to assign one reason, amongst many, for my conviction that nothing but personal communication can enable our manufactures to be transplanted.

301.  In many instances it is exceedingly difficult to estimate beforehand the sale of an article, or the effects of a machine; a case, however, occurred during a recent enquiry, which although not quite appropriate as an illustration of probable demand, is highly instructive as to the mode of conducting investigations of this nature.  A committee of the House of Commons was appointed to enquire into the tolls proper to be placed on steam-carriages; a question, apparently, of difficult solution, and upon which widely different opinions had been formed, if we may judge by the very different rate of tolls imposed upon such carriages by different ‘turnpike trusts’.  The principles on which the committee conducted the enquiry were, that ’The only ground on which a fair claim to toll can be made on any public road, is to raise a fund, which, with the strictest economy, shall be just sufficient—­first, to repay the expense of its original formation; secondly, to maintain it in good and sufficient repair.’  They first endeavoured to ascertain, from competent persons, the effect of the atmosphere alone in deteriorating a well-constructed road.  The next step was, to determine the proportion in which the road was injured, by the effect of the horses’ feet compared with that of the wheels.  Mr Macneill, the superintendent, under Mr Telford, of the Holyhead roads, was examined, and proposed to estimate the relative injury, from the comparative quantities of iron worn off from the shoes of the horses, and from the tire of the wheels.  From the data he possessed, respecting the consumption of iron for the tire of the wheels, and for the shoes of the horses, of one of the Birmingham day-coaches, he estimated the wear and tear of roads, arising from the feet of the horses, to be three times as great as that arising from the wheels.  Supposing repairs amounting to a hundred pounds to be required on a road travelled over by a fast coach at the rate of ten miles an hour, and the same amount of injury to occur on another road, used only by waggons, moving at the rate of three miles an hour, Mr Macneill divides the injuries in the following proportions: