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See also:LOGARITHM (from Gr. Abyos, word, ratio, and apx0µos, number)
, in See also:mathematics, a word invented by See also: In the See also:case of fractional numbers (i.e. numbers in which the integral part is o) the mantissa is still kept See also:positive, so that, for example, log .25613 =7.4084604, log •0025613 =_3.4084604, &c . the minus sign being usually written over the characteristic, and not before it, to indicate that the characteristic only, and not the whole expression, is negative; thus 1.4084604 stands for—1+ '4084604 . The fact that when the base is to the mantissa of the logarithm is See also:independent of the position of the decimal point in the number affords the See also:chief See also:reason for the choice of to as base . The ex-planation of this See also:property of the base to is evident, for a See also:change in the position of the decimal points amounts to multiplication or division by some power of to, and this corresponds to the addition or subtraction of some integer in the case of the logarithm, the mantissa therefore remaining intact . It should be mentioned that in most tables of trigonometrical functions, the number to is added to all the logarithms in the table in See also:order to avoid the use of negative characteristics, so that the characteristic 9 denotes in reality 1, 8 denotes 2, 10 denotes o, &c . Logarithms thus increased are frequently referred to for the sake of distinction as See also:tabular logarithms, so that the tabular logarithm =the true logarithm + lo . In tables of logarithms of numbers to base to the mantissa only is in See also:general tabulated, as the characteristic of the logarithm of a number can always be written down at sight, the See also:rule being that, if the number is greater than unity, the characteristic is less by unity than the number of digits in the integral portion of it, and that if the number is less than unity the characteristic is negative, and is greater by unity than the number of ciphers between the decimal point and the first significant figure . It follows very simply from the definition of a logarithm that log. b X loge a = I , logo m = log. m X (I /log. b) . The second of these relations is an important one, as it shows that from a table of logarithms to base a, the corresponding table of logarithms to base b may be deduced by multiplying all the logarithms in the former by the See also:constant multiplier 1/log.b, which is called the modulus of the See also:system whose base is b with respect to the system whose base is a . The two systems of logarithms for which extensive tables have been calculated are the Napierian, or hyperbolic, or natural system, of which the base is e, and the Briggian, or decimal, or See also:common system, of which the base is ro; and we see that the logarithms in the latter system may be deduced from those in the former by multiplication by the constant multiplier 1/logeio, which is called the modulus of the common system of logarithms . The numerical value of this modulus is o•43429 44819 03251 82765 11289 . . ., and the value of its reciprocal, loge 10 (by multiplication by which Briggian logarithms may be converted into Napierian logarithms) is 2.30258 50929 94045 68401 79914 . . The quantity denoted by e is the See also:series, I+I+ T + I + I + ... I I.2 1.2.3 1.2.3.4 the numerical value of which is, 2.71828 18284 59045 23536 02874 . The logarithmic Function.—The mathematical function log x or loge x is one of the small See also:group of transcendental functions, consisting only of the circular functions (See also:direct and inverse) sin x, See also:cos x, &c., arc sin x or sin-1 x,&c., log x and ee which are universally treated I in analysis as known functions . The notation log x is generally employed in See also:English and See also:American See also:works, but on the' See also:continent of See also:Europe writers usually denote the function by 1x or lg x . The logarithmic function is most naturally introduced into analysis by the equation logy= J tt (x>o) . This equation defines log x for positive values of x; if x10 o the See also:formula ceases to have any meaning . Thus log x is the integral function of I/x, and it can be shown that log x is a genuinely new transcendent, not expressible in finite terms by means of functions such as algebraical or circular functions . A connexion with the circular functions, however, appears later when the definition of log x is extended to complex values of x . A relation which is of See also:historical See also:interest connects the logarithmic function with the See also:quadrature of the See also:hyperbola, for, by considering the equation of the hyperbola in the See also:form xy=const., it is evident that the See also:area included between the arc of a hyperbola, its nearest asymptote, and two ordinates See also:drawn parallel to the other asymptote from points on the first asymptote distant a and b from their point of intersection, is proportional to log b/a . The following fundamental properties of log x are readily deducible from the definition (i.) log xy=log x+log y . (ii.) Limit of (x" -1)/h = log x, wken h is indefinitely diminished . Either of these properties might be taken as itself the definition of log x . There is no series for log x proceeding either by ascending or descending powers of x, but there is an expansion for log (1+x), viz . log (I+x)=x—zx2+1x3—zx'+ ... ; the series, however, is convergent for real values of x only when x lies between +1 and - I . Other formulae which are deducible from this equation are given in the portion of this See also:article See also:relating to the calculation of logarithms . The function log x as x increases from o towards so steadily in-creases frokri -so towards +so . It has the important property that it tends to Infinity with x, but more slowly than any power of x, i.e. that x-" log x tends to zero as x tends to so for every positive value of m however small . The exponential function, exp x, may be defined as the inverse of the logarithm: thus x=exp y if y = log x . It is positive for all values of y and increases steadily from o toward so as y increases from -eo towards + so . As y tends towards so , exp y tends towards so more rapidly than any power of y . The exponential function possesses the properties (i.) exp (x+y) =exp x X exp y . d (u.) Tx exp x =exp x . (iii.) exp x = t +x+x2/2 ! + x3/3 ! + .. . From (i.) and (ii.) it may be deduced that exp x=(1+1+1/2 1 +1/3 ! + ...)r, where the right-See also:hand See also:side denotes the positive xth power of the number 1+I+1/2 ! +1/3 ! + ... usually denoted by e . It is customary, therefore, to denote the exponential function by See also:ea, and the result ex = I +x+x2/2 ! +x3/3 ! . • • is known as the exponential theorem . The See also:definitions of the logarithmic and exponential functions may be extended to complex values of x . Thus if x=E+in, log x= ( — Ji t where the path of integration in the See also:plane of the complex variable t is any See also:curve which does not pass through the origin; but now log x is not a See also:uniform function, that is to say, if x describes a closed curve it does not follow that log x also describes a closed curve: in fact we have log (E+in) =logs/ (E2+n2)+i(a+2nir), where a is the numerically least See also:angle whose cosine and sine are (E'+n2) and n/sl (E'+n2), and n denotes any integer . Thus even when the See also:argument is real log x has an See also:infinite number of values; for putting n=o and taking E positive, in which case a=o, we obtain for log the infinite system of values log E+2n1ri . It follows from this property of the function that we cannot have for log x a series which shall be convergent for all values of x, as is the case with sin x and cos x, for such a series could only represent a uniform function, and in fact the equation i_ log(1 +x) =x—1x2+1 9x'—1x4+ .. . is true only when the analytical modulus of x is less than unity . The exponential function, which may still be defined as the inverse of the logarithmic function, is, on the other hand, a uniform function of x, and its fundamental properties may be stated in the same form as for real values of x . Also exp (E=ef (cos n+i sin ,t) . An alternative method of developing the theory of the exponential function is to start from the definition exp x = I .l-x+x2/2 ! +x3/3 ! + ... , the series on the right-hand being convergent for all values of x and therefore defining an analytical function of x which is uniform and See also:regular all over the plane . Invention and See also:Early See also:History of Logarithms.—The invention of logarithms has been accorded to John Napier, See also:baron of Merchiston in See also:Scotland, with a unanimity which is rare with regard to important scientific discoveries: in fact, with the exception o1 the tables of Justus Byrgius, which will be referred to further on, there seems to have been no other mathematician of the See also:time whose mind had conceived the principle on which logarithms depend, and no partial anticipations of the See also:discovery are met with in previous writers . The first announcement of the invention was made in Napier's hlirifici Logarilhmorum Canonis Descriptio . . . (See also:Edinburgh, 1614) .
The See also:work is a small See also:quarto containing fifty-seven pages of explanatory matter and a table of ninety pages (see NAPIER, JoHN)
.
The nature of logarithms is explained by reference to the See also:motion of points in a straight See also:line, and the principle upon which they are based is that of the See also:correspondence of a geometrical and an arithmetical series of numbers
.
The table gives the logarithms of sines for every See also:minute of seven figures; it is arranged semi-quadrantally, so that the differentiae, which are the See also:differences of the two logarithms in the same line, are the logarithms of the tangents
.
Napier's logarithms are not the logarithms now termed Napierian or hyperbolic, that is to say,logarithms to the base e where e= 2.7182818 .; the relation between N (a sine) and L its logarithm, as defined in the Canonis Descriptio, being N= 1o7e L/Ip7, so that (ignoring the factors Io7, the effect of which is to render sines and logarithms integral to
7 figures), the base is Napier's logarithms decrease as the sines increase
.
If 1 denotes the logarithm to base e (that is, the so-called "Napierian " or hyperbolic logarithm) and L denotes, as above, " Napier's " logarithm, the connexion between l and L is expressed by
L = Io, loge Io7 — Io71 or et = I07e—L/103
Napier's work (which will henceforth in this article be referred to as the Descriptio) immediately on its See also:appearance in 1614 attracted the See also:attention of perhaps the two most eminent English mathematicians then living—See also:Edward See also:Wright and See also:
Therefore it may please you who are inclined to these studies, to receive it from me and the Translator, with as much good will as we recommend it unto you." There is a See also:short " preface to the reader " by Briggs, and a description of a triangular See also:diagram invented by Wright for finding the proportional parts
.
The table is printed to one figure less than in the Descriptio
.
Edward Wright died, as has been mentioned, in 1615, and his son, See also:Samuel Wright, in the preface states that his See also:father " gave much See also:commendation of this work (and often in my See also:hearing) as of very See also:great use to mariners "; and with respect to the translation he says that " shortly after he had it returned out of Scotland, it pleased See also:God to See also:call him away afore he could publish it." The translation was published in 1616
.
It was also reissued with a new See also:title-See also:page in 1618
.
Henry Briggs, then See also:professor of See also:geometry at See also:Gresham College, See also:London, and afterwards Savilian professor of geometry at See also:Oxford, welcomed the Descriptio with See also:enthusiasm
.
In a letter to See also:Arch-See also:bishop See also:Usher, dated Gresham See also:House, See also:
Briggs's Logarithmorum chilias prima, which contains the first published table of decimal or common logarithms, is only a small See also:octavo See also:tract of sixteen pages, and gives the logarithms of numbers from unity to l000 to 14 places of decimals
.
It was published, probably privately, in 1617, after Napier's death,' and there is no author's name, place or date
.
The date of publication is, however, fixed as 1617 by a letter from See also:Sir Henry See also:Bourchier to Usher, dated See also:December 6, 1617, containing the passage—" Our See also:kind friend, Mr Briggs, hath lately published a supplement to the most excellent tables of logarithms, which I presume he has sent to you." Briggs's tract of 1617 is extremely rare, and has generally been ignored or incorrectly described
.
See also:Hutton erroneously states that it contains the logarithms to 8 places, and his account has been followed by most writers
.
There is a copy in the See also:British Museum
.
Briggs continued to labour assiduously at the calculation of logarithms, and in 1624 published his Arithmetica logarithmica, a See also:folio work containing the logarithms of the numbers from t to 20,000, and from 90,000 to 1oo,000 (and in some copies to 101,000) to 14 places of decimals
.
The table occupies 300 pages, and there is an introduction of 88 pages relating to the mode of calculation, and the applications of logarithms
.
There was thus See also:left a See also:gap between 20,000 and 90,000, which was filled up by See also:Adrian Vlacq (or Ulaccus), who published at See also:Gouda, in See also: . London, printed by See also:George See also:Miller, 1631 . There are also copies with the title-page and introduction in See also:French and in Dutch (Gouda, 1628) . Briggs had himself been engaged in filling up the gap, and in a letter to John See also:Pell, written after the publication of Vlacq's work, and dated See also:October 25, 1628, he says: " My See also:desire was to have those chiliades that are wantinge betwixt 20 and 90 calculated and printed, and I had done them all almost by my selfe, and by some frendes whom my rules had sufficiently in-formed, and by agreement the busines was conveniently parted amongst us; but I am eased of that See also:charge and care by one Adrian Vlacque, an Hollander, who hathe done all the whole See also:hundred chiliades and printed them in Latin, Dutche and Frenche, moo bookes in these 3 See also:languages, and hathe could them almost all . But he hathe cutt off 4 of my figures throughout; and hathe left out my See also:dedication, and to the reader, and two chapters the 12 and 13, in the See also:rest he hafh not varied from me at all." The original calculation of the logarithms of numbers from unity to rot,o0o was thus performed by Briggs and Vlacq between 1615 and 1628 . Vlacq's table is that from which all the hundreds of tables of logarithms that have subsequently appeared have been derived . It contains of course many errors, which were gradually discovered and corrected in the course of the next two hundred and fifty years . The first calculation or publication of Briggian or common iogarithms of trigonometrical functions was made in 162o by See also:Edmund See also:Gunter, who was Briggs's colleague as professor of ' It was certainly published after Napier's death, as Briggs mentions his " librum posthumum." This See also:liber posthumus was the Lonstructio referred to later in this article.See also:astronomy in Gresham College . The title of Gunter's book, which is very scarce, is See also:Canon triangulorum, and it contains logarithmic sines and tangents for every minute of the quadrant to 7 places of decimals . • The next publication was due to Vlacq, who appended to his logarithms of numbers in the Arithmetica logarithmica of 1628 a table giving log sines, tangents and secants for every minute of the quadrant to to places; there were obtained by calculating the logarithms of the natural sines, &c. given in the See also:Thesaurus mathematicus of Pitiscus (1613) . During the last years of his life Briggs devoted himself to the calculation of logarithmic sines, &c. and at the time of his death in 1631 he had all but completed a logarithmic canon to every hundredth of a degree . This work was published by Vlacq at his own expense at Gouda in 1633, under the title Trigonometria Britannica . It contains log sines (to 14 places) and tangents (to to places), besides natural sines, tangents and secants, at intervals of a hundredth of a degree . In the same See also:year Vlacq published at Gouda his Trigonometria artificialis, giving log sines and tangents to every 10 seconds of the quadrant to to places . This work also contains the logarithms of numbers from unity to 20,000 taken from the Arithmetica logarithmica of 1628 . Briggs appreciated clearly the advantages of a centesimal, division of the quadrant, and by dividing the degree into hundredth parts instead of into minutes, made a step towards a See also:reformation in this respect, and but for the appearance of Vlacq's work the decimal division of the degree might have become recognized, as is now the case with the corresponding division of the second . The calculation of the logarithms not only of numbers but also of the trigonometrical functions is therefore due to Briggs and Vlacq; and the results contained in their four fundamental works—Arithmetica logarilhmica (Briggs), 1624; Arithmetica logarithmica (Vlacq), 1628; Trigonometria Britannica (Briggs), 1633; Trigonometric artificialis (Vlacq), 1633—have not been superseded by any subsequent calculations . In the preceding paragraphs an account has been given of the actual announcement of the invention of logarithms and of the calculation of the tables . It now remains to refer in more detail to the invention itself and to examine the claims of Napier and Briggs to the See also:capital improvement involved in the change from Napier's original logarithms to logarithms to the base to . The Descriptio contained only an explanation of the use of the logarithms without any account of the manner in which the canon was constructed . In an " Admonitio " on the seventh page Napier states that, although in that place the mode of construction should be explained, he proceeds at once to the use of the logarithms, " ut praelibatis prius usu, et rei utilitate, caetera See also:aut magis placeant posthac edenda, aut minus saltem displiceant silentio sepulta." He awaits therefore the See also:judgment and censure of the learned " priusquam caetera in lucem temere prolata lividorum detrectationi exponantur "; and in an " Admonitio " on the last page of the book he states that he will publish the mode of construction of the canon " si huius inventi usum eruditis gratum fore intellexero." Napier, however, did not live to keep this promise . In 1617 he published a small work entitled Rabdologia relating to See also:mechanical methods of performing multiplications and divisions, and in the same year he died . The proposed work was published in 1619 by See also:Robert Napier, his second son by his second See also:marriage, under the title Mirifici logarithmorum canonis constructio . . . . It consists of two pages of preface followed by sixty-seven pages of See also:text . In the preface Robert Napier says that he has been assured from undoubted authority that the new invention is much thought of by the ablest mathematicians, and that nothing would delight them more than the publication of the mode of construction of the canon . He therefore issues the work to satisfy their desires, although, he states, it is See also:manifest that it would have seen the See also:light in a far more perfect See also:state if his father could have put the See also:finishing touches to it; and he mentions that, in the See also:opinion of the best See also:judges, his father possessed, among other most excellent gifts, in the highest degree the power of explaining the most difficult matters by a certain and easy method in the fewest possible words . It is important to See also:notice that in the Constructio logarithms are called artificial numbers; and Robert Napier states that the work was composed several years (See also:aliquot annos) before Napier had invented the name logarithm . The Constructio therefore may have been written a good many years previous to the publication of the Descriptio in 1614 . Passing now to the invention of common or decimal logarithms, that is, to the transition from the logarithms originally invented by Napier to logarithms to the base 10, the first allusion to a change of system occurs in the "Admonitio " on the last page of the Descriptio (1614), the concluding See also:paragraph of which is " Verum si huius inventi usum eruditis gratum fore intellexero, dabo fortasse brevi (Deo aspirante) rationem ac methodum aut hunc canonem emendandi, aut emendatiorem de novo condendi, ut ita plurium Logistarum diligentia,limatior tandem et accuratior, quam unius See also:opera fieri potuit, in lucem prodeat . Nihil in ortu perfectum." In some copies, however, this " Admonitio " is absent . In Wright's translation of 1616 Napier has added the See also:sentence—" But because the addition and subtraction of these former numbers may seeme somewhat painfull, I intend (if it shall please God) in a second Edition, to set out such Logarithmes as shall make those numbers above written to fall upon decimal numbers, such as 100,000,000, 200,000,000, 300,000,000, &c., which are easie to be added or See also:abated to or from any other number " (p..19); and in the dedication of the Rabdologia (1617) he wrote " See also:Quorum quidem Logarithmorum speciem aliam multo praestantiorem nunc etiam invenimus, & creandi methodum, una cum eorum usu (si See also:Deus longiorem vitae & valetudinis usuram concesserit) evulgare statuimus; ipsam autem novi canonis supputationem, ob infirmam corporis nostri valetudinem, viris in hoc studii genere versatis relinquimus: imprimis vero doctissimo viro D . Henrico Briggio Londini publico Geometriae Professori, et amico mihi longe charissimo." Briggs in the short preface to his Logarithmorum chilias (1617) states that the reason why his logarithms are different from those introduced by Napier " sperandum, ejus librum See also:post humum, abunde nobis propediem satisfacturum." The " liber posthumus " was the Constructio (1619), in the preface to which Robert Napier states that he has added an appendix relating to another and more excellent See also:species of logarithms, referred to by the inventor himself in the Rabdologia, and in which the logarithm of unity is o . He also mentions that he has published some remarks upon the propositions in spherical See also:trigonometry and upon the new species of logarithms by Henry Briggs, "qui novi hujus Canonis supputandi laborem gravissimum, See also:pro singulari amicitia quae illi cum Patre meo L . M. intercessit, animo libentissimo in se suscepit; creandi methodo, et usuum explanatione Inventori relictis . Nunc autem ipso ex See also:lac vita evocato, totius negotii onus doctissimi Briggii humeris incumbere, et See also:Sparta haec ornanda illi sorte quadam obtigisse videtur." In the address prefixed to the Arithmetica logarithmica (1625) Briggs bids the reader not to be surprised that these logarithms are different from those published in the Descriptio : " Ego enim, cum meis auditoribus Londini, publice in Collegio Greshamensi horum doctrinam explicarem; animadverti multo futurum commodius, si Logarithmus sinus totius servaretur o (ut in Canone mirifico), Logarithmus autem partis decimae ejusdem sinus totius, nempe sinus 5 graduum, 44, M . 21, s., esset l0000000000. atque ea de re scripsi statim ad ipsum authorem, et quamprimum per anni tempos, et vacationem a publico docendi munere licuit, profectus sum Edinburgum; ubi humanissime ab eo acceptus hacsi per integram mensem: Cum autem inter nos de horum mutatione sermo haberetur; ille se idem dudum sensisse, et cupivisse dicebat: veruntamen istos, quos jam paraverat edendos curasse, donee alios, si per negotia et valetudinem liceret, magis commodos confecisset .
Istam autem mutationem ita faciendam censebat, ut o esset Logarithmus unitatis, et t0000000000 sinus totius: quod ego longe commodissimum esse non potui non agnoscere
.
Coepi igitur, ejus hortatu, rejectis illis quos antea paraveram, de horum calculo serio cogitare; et sequenti aestate iterum profectus Edinburgum, horum quos hic exhibeo praecipuos. ostendi, idem etiam tertia aestate libentissime facturus, si Deus ilium nobis tamdiu superstitem esse voluisset."
There is also a reference to the change of the logarithms on the title-page of the work
.
These extracts contain all the original statements made by Napier, Robert Napier and Briggs which have reference to the origin of decimal logarithms
.
It will be seen that they are all in perfect agreement
.
Briggs pointed out in his lectures at Gresham College that it would be more convenient that o should stand for the logarithm of the whole sine as in the Descriptio, but that the logarithm of the tenth part of the whole sine should be ro,000,000,000
.
He wrote also to Napier at once; and as soon as he could he went to Edinburgh to visit him, where, as he was most hospitably received by him, he remained for a whole month
.
When they conversed about the change of system, Napier said that he had perceived and desired the same thing, but that he had published the tables which he had already pre-pared, so that they might be used until he could construct others more convenient
.
But he considered that the change ought to be so made that o should be the logarithm of unity and 10,000,000,000 that of the whole sine, which Briggs could not but admit was by far the most convenient of all
.
Rejecting therefore, those which he had prepared already, Briggs began, at Napier's See also:advice, to consider seriously the question of the calculation of new tables
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In the following summer he went to Edinburgh and showed Napier the principal portion of the logarithms which he published in 1624
.
These probably included the logarithms of the first chiliad which he published in 1617
.
It has been thought necessary to give in detail the facts relating to the See also:conversion of the logarithms, as unfortunately See also: . . which occur in the preface to the Chilias, were a modest hint that the share Briggs had had in changing the logarithms should be mentioned, and that, as no attention was paid to it, he himself gave the account which appears in the Arithmetica of 1624 . There seems, however, no ground whatever for supposing that Briggs meant to See also:express anything beyond his hope that the reason for the alteration would be explained in the posthumous work; and in his own account, written seven years after Napier's death and five years after the appearance of the work itself, he shows no injured feeling whatever, but even goes out of his way to explain that he abandoned his own proposed alteration in favour of Napier's, and, rejecting the tables he had already constructed, began to consider the calculation of new ones . The facts, as stated by Napier and Briggs, are in See also:complete accordance, and the friendship existing between them was perfect and unbroken to the last . Briggs assisted Robert Napier in the editing of the " posthumous work," the Constructio, and in the account he gives of the alteration of the logarithms in the Arithmetica of 1624 he seems to have been more anxious that See also:justice should be done to Napier than to him-self; while on the other hand Napier received Briggs most hospitably and refers to him as " amico mihi longe charissimo." Hutton's suggestions are all the more to be regretted as they occur as a history which is the result of a good See also:deal of investigation and which for years was referred to as an authority by many writers . His See also:prejudice against Napier naturally produced See also:retaliation, and See also:Mark Napier in defending his ancestor has fallen into the opposite extreme of attempting to reduce Briggs to the level of a See also:mere computer . In connexion with this controversy it should be noticed that the " Admonitio " on the last page of the Descriptio, containing the reference to the new logarithms, does not occur in all the copies . It is printed on the back of the last page of the table itself, and so cannot have been torn out from the copies that are without it . As there could have been no reason for omitting it after it had once appeared, we may assume that the copies which do not have it are those which were first issued . It is probable, therefore, that Briggs's copy contained no reference to the change, and it is even possible that the "Admonitio " may have been added after Briggs had communicated with Napier . As See also:special attention has not been drawn to the fact that some copies have the " Admonitio " and some have not, different writers have assumed that Briggs did or did not know of the promise contained in the " Admonitio " according as it was See also:present or absent in the copies they had themselves referred to, and this has given rise to some confusion . It may also be remarked that the date frequently assigned to Briggs's first visit to Napier is 1616, and not 1615 as stated above, the reason being that Napier was generally supposed to have died in 1618 until Mark Napier showed that the true date was 1617 . When the Descriplio was published Briggs was fifty-seven years of See also:age, and the remaining seventeen years of his life were devoted with steady enthusiasm to extend the utility of Napier's great invention . The only other mathematician besides Napier who grasped the See also:idea on which the use of logarithm depends and applied it to the construction of a table is Justus Byrgius (See also:Jobst Biirgi), whose work Ariihmetische send geometrische Progress-Tabulen ... was published at See also:Prague in 162o, six years after the publication of the Descriptio of Napier . This table distinctly involves the principle of logarithms and may be described as a modified table of antilogarithms . It consists of two series of numbers, the one being an arithmetical and the other a geometrical progression: thus 0, 1.0000 0000 I O, I ,000I 0000 20, 1,0002 0001 990, 1,0099 4967 In the arithmetical See also:column the numbers increase by Io, in the geometrical column each number is derived from its predecessor by multiplication by i•000i . Thus the number lox in the arithmetical column corresponds to Ioe (i.000l)s in the geometrical column; the intermediate numbers being obtained by See also:interpolation . If we See also:divide the numbers in the geometrical column by rob the correspondence is between iox and (1•000l)s, and the table then becomes one of antilogarithms, the base being (1.0001)1/10, viz. for example (I•o0o1)i16•990=x•00994967 . The table extends to 230270 in the arithmetical column, and it is shown that 230270.022 corresponds to 9'9999 9999 or 109 in the geometrical column; this last result showing that (i•000 1)23027.022 = ro . The first contemporary mention of Byrgius's table occurs on page II of the " Praecepta " prefixed to See also:Kepler's Tabulae Radolphinae (1627); his words are: " apices logistici J . Byrgio multis annis ante editionem Neperianam viam praeiverent ad hos ipsissimos logarithmos . Etsi homo cunctator et secretorum suorum custos foetum in partu destituit, non ad usus publicos educavit." Another reference to Byrgius occurs in a work by See also:Benjamin Bramer, the See also:brother-in-See also:law and See also:pupil of Byrgius, who, See also:writing in 163o, says that the latter constructed his table twenty years ago or more.' As regards priority of publication, Napier has the See also:advantage by six years, and even fully accepting Bramer's statement, there are grounds for believing that Napier's work See also:dates from a still earlier See also:period . The power of to, which occurs as a See also:factor in the tables of both Napier and Byrgius, was rendered necessary by the fact that the decimal point was not yet in use . Omitting this factor in ' Frisch's Kepleri opera omnia, ii . 834 . Frisch thinks Bramer possibly relied on Kepler's statement quoted in the text (" Quibus forte confisus Kepleri verbis Benj . Bramer . . . ") . See also vol. vii. p . 298 . The claims of Byrgius are discussed in Kastner's Geschichte der Mathematik, ii . 375, and iii . 14; See also:Montucla's Histoire See also:des mathematigues, ii . Io; See also:Delambre's Histoire de l'astronomie moderne, i . 560; de See also:Morgan's article on " Tables " in the English Cyclopaedia ; Mark Napier's See also:Memoirs of John Napier of Merchiston (1834), p . 391, and Cantor's Geschichte der Mathematik, ii . (1892), 662 . See also Gieswald, Justus Byrg als Mathematiker and dessen Einleitung in See also:seine Logarithmen (See also:Danzig, 1856).the case of both tables, the connexion between N a number and L its " logarithm " is N=(e')'' (Napier), L=(1•000l)See also:ioo (Byrgius), viz . Napier gives logarithms to base e 1, Byrgius gives See also:anti-logarithms to base (1•000i)I'a . There is indirect See also:evidence that Napier was occupied with logarithms as early as 1594, for in a letter to P . Crugerus from Kepler, dated See also:September 9, 1624 (Frisch's Kepler, vi . 47), there occurs' the sentence: " Nihil autem supra Neperianam rationem ease puto: etsi quidem Scotus quidam literis ad Tychonem 1594 scriptis jam spem fecit Canonis illius Mirifici." It is here distinctly stated that some Scotsman in the year 1594, in g. letter to Tycho See also:Brahe, gave him some hope of the logarithms; and as Kepler joined Tycho after his See also:expulsion from the island of Huen, and had been so closely associated with him in his work, he would be likely to be correct in any assertion of this kind . In connexion with Kepler's statement the following See also:story, told by See also: |