Slide Rule is in Scientific Terms.
Around 1662 William Oughtred Mathematician invented the Slide Rule.
Pepy's Diary. 14 Apr 1663. Up betimes to my office, where busy till 8 o'clock that Sir W. Batten (age 62), Sir J. Minnes (age 64), Sir W. Pen (age 41) and I down by barge to Woolwich [Map], to see "The Royal James" launched, where she has been under repair a great while. We staid in the yard till almost noon, and then to Mr. Falconer's to a dinner of fish of our own sending, and when it was just ready to come upon the table, word is brought that the King (age 32) and Duke (age 29) are come, so they all went away to shew themselves, while I staid and had a little dish or two by myself, resolving to go home, and by the time I had dined they came again, having gone to little purpose, the King (age 32), I believe, taking little notice of them. So they to dinner, and I staid a little with them, and so good bye. I walked to Greenwich [Map], studying the Slide Rule for measuring of timber, which is very fine.
Pepy's Diary. 05 May 1663. In the evening Deane of Wollwich (age 29) went home with me and showed me the use of a little sliding ruler, less than that I bought the other day, which is the same with that, but more portable; however I did not seem to understand or even to have seen anything of it before, but I find him an ingenious fellow, and a good servant in his place to the King.
Pepy's Diary. 06 May 1663. Up betimes and to my office a good while at my new rulers, then to business, and towards noon to the Exchange [Map] with Creed, where we met with Sir J. Minnes (age 64) coming in his coach from Westminster, who tells us, in great heat, that, by God, the Parliament will make mad work; that they will render all men incapable of any military or civil employment that have borne arms in the late troubles against the King, excepting some persons; which, if it be so, as I hope it is not, will give great cause of discontent, and I doubt will have but bad effects.
Pepy's Diary. 11 May 1663. So to the yard a little, and thence on foot to Greenwich [Map], where going I was set upon by a great dogg, who got hold of my garters, and might have done me hurt; but, Lord, to see in what a maze I was, that, having a sword about me, I never thought of it, or had the heart to make use of it, but might, for want of that courage, have been worried. Took water there and home, and both coming and going did con my lesson on my Ruler to measure timber, which I think I can well undertake now to do. At home there being Pembleton I danced, and I think shall come on to do something in a little time, and after dinner by coach with Sir W. Pen (age 42) (setting down his daughter at Clerkenwell), to St. James's, where we attended the Duke of York (age 29): and, among other things, Sir G. Carteret (age 53) and I had a great dispute about the different value of the pieces of eight rated by Mr. Creed at 4s. and 5d., and by Pitts at 4s. and 9d., which was the greatest husbandry to the King (age 32)? he persisting that the greatest sum was; which is as ridiculous a piece of ignorance as could be imagined. However, it is to be argued at the Board, and reported to the Duke next week; which I shall do with advantage, I hope.
Pepy's Diary. 11 Jun 1663. Up and spent most of the morning upon my measuring Ruler and with great pleasure I have found out some things myself of great dispatch, more than my book teaches me, which pleases me mightily. Sent my wife's things and the wine to-day by the carrier to my father's, but staid my boy from a letter of my father's, wherein he desires that he may not come to trouble his family as he did the last year.
Pepy's Diary. 18 Jul 1663. Up and to my office, where all the morning, and Sir J. Minnes (age 64) and I did a little, and but a little business at the office. So I eat a bit of victuals at home, and so abroad to several places, as my bookseller's, and then to Thomson the instrument maker's (age 25) to bespeak a ruler for my pocket for timber, &c., which I believe he will do to my mind.
Pepy's Diary. 07 Aug 1663. Thence home and to study my new rule till my head aked cruelly. So by and by to dinner and the Doctor and Mr. Creed came to me. The Doctor's discourse, which (though he be a very good-natured man) is but simple, was some sport to me and Creed, though my head akeing I took no great pleasure in it. We parted after dinner, and I walked to Deptford [Map] and there found Sir W. Pen (age 42), and I fell to measuring of some planks that was serving into the yard, which the people took notice of, and the measurer himself was amused at, for I did it much more ready than he, and I believe Sir W. Pen (age 42) would be glad I could have done less or he more.
Pepy's Diary. 07 Aug 1663. Up and to my office a little, and then to Brown's for my measuring rule, which is made, and is certainly the best and the most commodious for carrying in one's pocket, and most useful that ever was made, and myself have the honour of being as it were the inventor of this form of it. Here I staid discoursing an hour with him and then home, and thither came Sir Fairbrother to me, and we walked a while together in the garden and then abroad into the cittie, and then we parted for a while and I to my Viall, which I find done and once varnished, and it will please me very well when it is quite varnished.
Pepy's Diary. 08 Aug 1663. Up and to my office, whither I search for Brown the mathematical instrument maker, who now brought me a ruler for measuring timber and other things so well done and in all things to my mind that I do set up my trust upon it that I cannot have a better, nor any man else have so good for this purpose, this being of my own ordering.
Pepy's Diary. 10 Aug 1663. After dinner I took leave and went to Greatorex's (age 38), whom I found in his garden, and set him to work upon my ruler, to engrave an almanac and other things upon the brasses of it, which a little before night he did, but the latter part he slubbered over, that I must get him to do it over better, or else I shall not fancy my rule, which is such a folly that I am come to now, that whereas before my delight was in multitude of books, and spending money in that and buying alway of other things, now that I am become a better husband, and have left off buying, now my delight is in the neatness of everything, and so cannot be pleased with anything unless it be very neat, which is a strange folly.
Pepy's Diary. 15 Aug 1663. So by water down to Deptford, taking into my boat with me Mr. Palmer, one whom I knew and his wife when I was first married, being an acquaintance of my wife's and her friends lodging at Charing Cross during our differences. He joyed me in my condition, and himself it seems is forced to follow the law in a common ordinary way, but seems to do well, and is a sober man, enough by his discourse. He landed with me at Deptford, where he saw by the officers' respect to me a piece of my command, and took notice of it, though God knows I hope I shall not be elated with that, but rather desire to be known for serving the King (age 33) well, and doing my duty. He gone I walked up and down the yard a while discoursing with the officers, and so by water home meditating on my new Rule with great pleasure.
Pepy's Diary. 06 Dec 1663. Lord's Day. Lay long in bed, and then up and to church alone, which is the greatest trouble that I have by not having a man or, boy to wait on me, and so home to dinner, my wife, it being a cold day, and it begun to snow (the first snow we have seen this year) kept her bed till after dinner, and I below by myself looking over my arithmetique books and timber rule.
Pepy's Diary. 24 Dec 1663. Thence back again, entertaining myself upon my sliding rule with great content, and called at Woolwich [Map], where Mr. Chr. Pett (age 43) having an opportunity of being alone did tell me his mind about several things he thought I was offended with him in, and told me of my kindness to his assistant. I did give him such an answer as I thought was fit and left him well satisfied, he offering to do me all the service, either by draughts or modells that I should desire.
Pepy's Diary. 10 Aug 1664. Up, and, being ready, abroad to do several small businesses, among others to find out one to engrave my tables upon my new sliding rule with silver plates, it being so small that Browne that made it cannot get one to do it. So I find out Cocker (age 33), the famous writing-master, and get him to do it, and I set an hour by him to see him design it all; and strange it is to see him with his natural eyes to cut so small at his first designing it, and read it all over, without any missing, when for my life I could not, with my best skill, read one word or letter of it; but it is use. But he says that the best light for his life to do a very small thing by (contrary to Chaucer's words to the Sun, "that he should lend his light to them that small seals grave"), it should be by an artificial light of a candle, set to advantage, as he could do it. I find the fellow, by his discourse, very ingenuous; and among other things, a great admirer and well read in all our English poets, and undertakes to judge of them all, and that not impertinently. Well pleased with his company and better with his judgement upon my Rule, I left him and home, whither Deane (age 30) by agreement came to me and dined with me, and by chance Gunner Batters's wife.
Pepy's Diary. 11 Aug 1664. He gone, I late to my office, and cannot forbear admiring and consulting my new rule, and so home to supper and to bed. This day, for a wager before the King (age 34), my Lords of Castlehaven (age 47) and Arran (age 25) (a son of my Lord of Ormond's (age 53)), they two alone did run down and kill a stoute bucke in St. James's parke.
Pepy's Diary. 11 Aug 1664. So home to dinner, and by and by comes Mr. Creed, lately come from the Downes, and dined with me. I show him a good countenance, but love him not for his base ingratitude to me. However, abroad, carried my wife to buy things at the New Exchange, and so to my Lady Sandwich's (age 39), and there merry, talking with her a great while, and so home, whither comes Cocker (age 33) with my rule, which he hath engraved to admiration, for goodness and smallness of work: it cost me 14s. The doing, and mightily pleased I am with it.