The fossil iguanodon.

Date:
1833
Catalogue details

Licence: Public Domain Mark

Credit: The fossil iguanodon. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    -7 gallons : to find the shillings and pence, as near as this rule can do it, we must deal with the 820 in such a manner as to reverse the process in (1) and (2); that is, we must ask what number of shillings and pence would have given us 820, if we had done with them what is directed to be done in (1) and (2). The reverse rule is ;— 1. Double the first figure, and add 1 if the second figure be 5 or upwards ; this is the number of shillings. It is 16 in this instance, since the second figure is not so great as 5. 2. Take away five from the second figure, if that can be done, and with the remainder and the third figure, or with the second and third figures form a number; which number diminish by 1 if it be 25 or upwards. In the present instance this gives simply 20, for the second figure is not so great as 5, nor is 20 so great as 25. If the number had been 887 instead of 820, we should have had 36; the 3 lefl from the 8 after 5 has been taken away giving 37, which is diminished by 1, because 37 is greater than 25. 3. Turn the last number, considered as farthings, into pence and farthings ; which gives, in this case, 5 pence. Hence the price of ten gallons by our rule is .£38. 16s. bd. The real price is £39. 16s. 5itd. To find the price of a hundred gallons annex two ciphers to 3SS2 and cut off three places. This gives 3S8/200, which, treated in the same way, gives £3SS. 4s. 0d. The real price is £388. 4s. Id. To find the price of a thousand gallons annex three ciphers to 38S2 and cut oil' three places, or, which is the same thing, annex no ciphers. This gives £3882. 0s. 0d.; the real price is £3SS2. 5s. 107. This rule, though it takes some time in the descrip- tion, may be done after a little practice by the head alone; but with great facility by writing down only as much as is in the following example :— If 1 gallon costs £42. 6s. 3\d. 42314 10 gallons cost £423. 2s. 9fid. 100 1000 £4231. 8s. 0d. £42314. 0s. Od. which are respectively too small by l^d., 1 Ad., and I Is. 8d. We write down the following examples, which the eader may verify by the rule :— If 1 costs £2. 0s. ll^d. 10 cost £20. 9s. bd. 100 „ £204. 14s. 0 d. 1000 „ £2047. 0s. Od. In this case, and in that where there is only one shil- ling, a cipher must be placed after the pounds. Thus the number from which these are deduced is 2047. If 1 costs £31. 9s. l|d 10 cost £314. 1 Is. bd. 100 „ £3145. 14s. Od. 1000 „ £31457. 0s. Od. If 1 costs £0. 19 10 cost £9. 16s. Od. 100 „ £9S. 0s. Od. 1000 „ £980. 0s. Od. The nde always gives too little, except in the case where the number of pence is exactly 6d„ in which case the answer is accurately true. For example, If 1 costs £2. 18s. 6d. 10 cost £29. 5s. Od. 100 „ £292. 10s. Od. 1000 „ £2925. 0s.' 0d. As it is very uncommon, when the price is above five 6hillings, to sell goods, except for an exact number of shillings and sixpence^, this case will be found very con- venient. We may now describe the reverse rule. Knowing how many 10, 100, 1000, &c. cost, convert the sum into one number, by the first rule, strike oil’three places, and os vmny more as there are cijdiers in the number named. For example, if 100 cost £4936. IS*. 7jd., how much does one cost? The number is 4936932, from which I strike off five places; viz., the three which arc struck ofl'in every case, and two for the 2 ciphers in 100. This-gives 49/36932 Retain only three figures on the right, or * 49/369 1 x* which gives, treated according to the second rule, £49. 7s. 4|d. for the price of one. This is within a farthing of the truth. We have put the rule in such a way that those who do not understand decimal fractions may avail them- selves of it. Those who understand decimals may be told that tliis process is a short- one for converting any number of shillings and pence into the corresponding decimal of a pound. Thus £1. 15s. 6fd. is £l-778 nearly. Our coinage might be altered so as to make this rule exact, without altering the quantity of copper which is now coined into a pound sterling. It would require that the copper which now goes to 960 farthings or 240 pence, should be divided into a thousuiul farthings or 250 pence, the penny being four farthings, as at present. Of these farthings 50 would go to a shilling, instead of 48 as at present; so that the shilling would be twelve-pence half- penny. This would be inconvenient, but not very much so; and the silver and gold coinage would remain entirely untouched. The difference between the old and new farthing would be only one twenty-fifth part of the. old farthing; so that if goods were sold at the same nomi- nal price, the loss to the seller would be about a farthing in sixpence; or if the same real price were to be kept, the old price might be turned into the new, with ex- ceeding accuracy, by adding a farthing for every six- pence. This would be very useful in the period of con- fusion which would elapse between the establishment of the new coinage and the death of the generation which was brought up under the old. It would become usual to sell goods by tens instead of dozens, which would very much facilitate arithmetical operations. VVe are not advocates of any such change, but rather the contrary; but we are convinced that if any alteration ever take place, this should be the one. We will only add that even at present a simple table, small enough to be engraved on wood or bone, which could be carried in the waistcoat pocketjs all that is necessary to work by this rule xvitfFperfect exactness to any extent. — THE FOSSIL IGUA'NOBON. The guana, or iguana, of the Wes£ TiTriies, of w hich a description and wood-cut were gived'W^ recejti number of this Magazine, appears to be the living type or repre- sentative of one of the largest and most extraordinary reptiles of a former world that has hitherto been found in a fossil state. The discovery of this animal, and of its structure and character, we owe to the scientific researches of Gideon Mantell, Esq., F.R.S., of Lewes in Sussex and a detailed account of its osteology, with plates, was given by that gentleman in the Philosophical Transactions, 1S25 ; and subsequently in an interesting work published in 1S27, entitled ‘Illustrations of the Geology of Tilgate Forest.’ From the close resem- blance of the bones and teeth to those of the guana, Mr. Mantell has named the fossil animal the iguanodon; but though there is a resemblance in structure between the living and the fossil animal, they differ enormously