I thanked him for thus enabling me to make my countrymen appreciate the excellence of Venetian workmanship, and purchased small samples of every kind of chain then manufactured. These, on my return to London, I weighed and measured, and referred to them in the economy of manufactures as illustrations of the different proportions in which skilled labour and price of raw material occur in the same class of manufactured articles. {376}
A friend of mine, then at Venice, again visited that city about five years afterwards. He subsequently informed me that he had purchased, at the manufactory I visited, samples of gold chains about an inch or two long, fixed on black velvet, and that it formed a regular article of trade in some demand.
〈PULSATIONS AND INSPIRATIONS.〉
A man may, without being a proficient in any science, and indeed with only the most limited knowledge of a small portion of it, yet make himself useful to those who are most instructed. However limited the path he may himself pursue, he will insensibly acquire other information in return for that which he can communicate. I will illustrate this by one of my own pursuits. I possess the slightest possible acquaintance with the vast fields of animal life, but at an early period I was struck by the numerical regularity of the pulsation and of the breathings. It appeared to me that there must exist some relation between these two functions. Accordingly, I took every opportunity of counting the numbers of the pulsations and of the breathings of various animals. The pig fair at Pavia and the book fair at Leipsic equally placed before me menageries in which I could collect such facts. Every zoological collection of living animals which I visited thus gained an additional interest, and occasionally excited the attention of those in charge of it to making a collection of facts relating to that subject. This led me at another period to generalize the subject of inquiry, and to print a skeleton form for the constants of the class mammalia. It was reprinted by the British Association at Cambridge in 1833, and also at Brussels in the ‘Travaux du Congress Général de Statistique,’ Brussels, 1853.
I have so frequently been mortified by having the {377} utterly-undeserved reputation of knowing everything that I was led to inquire into the probable grounds of the egregious fallacy. The most frequent symptom was an address of this kind:—“Now Mr. Babbage, will you, who know everything, kindly explain to me — — —.” Perhaps the thing whose explanation was required might be the metre of some ancient Chinese poem: or whether there were any large rivers in the planet Mercury.
〈HOW TO PUNCH A HOLE IN GLASS.〉
One of the most useful accomplishments for a philosophical traveller with which I am acquainted, I learned from a workman, who taught me how to punch a hole in a sheet of glass without making a crack in it.
The process is very simple. Two centre-punches, a hammer, an ordinary bench-vice, and an old file, are all the tools required. These may be found in any blacksmith’s shop. Having decided upon the part of the glass in which you wish to make the hole, scratch a cross (