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  1. The Chinese unit "Moo" , spelled "Mou", is included in the list of foreign units in the 1911 E.B. article. Interesting that it was still in use nearly a century later. Defined as: " Commonly 806.65 sq. yds. Varies locally. Shanghai = 6600 sq. ft. (Municipal Council). By Customs Treaty, = 920.417 sq. yds., based on ch'ih of 14.1 inches. " The rather lengthy entry for the ch'ih iteslf says it can be anywhere between 11" and 15.8". 6 different definitions were used in Pekin alone, two different ones for public works, others for statistics, architects, "common", and mathematics. Yes, metric does have its place!
  2. Partially compensated for by the US fluid ounce being slightly bigger than the Imperial fluid ounce (1 US Fl. oz = 1.04 UK Fl. oz), I believe as a consequence of the respective fluid ounces being determined in terms of the same respective masses of water measured at different temperatures.
  3. Thanks for posting the old notice. I believe that the ton of 40 cubic feet is still used internationally to estimate the cargo-carrying capacity of ships' holds. There is also the register ton of 100 cubic feet used for measuring the internal capacity of merchant ships for the purpose of registration, and the ton displacement of 35 cubic feet of sea water, used for other vessels such as battleships, representing the amount of sea water displaced and hence the actual weight of the vessel. Funnily enough, yesterday I came across an old post in this thread from September 2010 on oil lamps where some sources of spares were given. On trying one in Germany I found they stock a replacement glass chimney for an oil lamp for which I had been unable to find a UK supplier for nearly a decade: result! Browsing their site, it appears that, in Europe, wick sizes for old lamps are still expressed in terms of "lines" of the inch of the old French foot. The old French foot was just over 13 English inches. The subdivision of 1 inch into 12 lines seems to have fallen into disuse in the UK in the inter-war period. I was never taught it at primary school in the early 1950's, but it appears in a table of weights and measures on the back cover of an old school exercise book dating from the 1920's. I have an old physics book which quotes verbatim passages from some of the early experimenters such as Newton. It seems that English physicists were then using the pre-decimal French units, such as the French foot (specifically, the Paris foot) and French pound. Interestingly, the metric metre, although said to represent an exact integer decimal submultiple of a quadrant of the earth's circumference, is almost exactly equal to three French feet, or half a French fathom (toise).
  4. The widespread existence of regional weights and measures before imperial standards were prescribed by law (I believe the Weights and Measures Act 1878, effective 1st Jan 1879) is indicated in a late Victorian arithmetic book I used to have. Its preface noted that it was a new edition that omitted the exercises in conversion between the local pounds, pints etc. that had previously been present. Until the present Imperial Gallon was made the legal standard in 1824, the Wine Gallon of 231 cubic inches (as still used in the USA) was the UK legal standard. Set into the wall behind the fountains at Trafalgar Square is a brass plaque with a standard Imperial yard and its subdivisions. The lengthy article "Weights and Measures" in the 1911 edition of the Encyclopaeidia Britannica says this about local usage: " Customary Weights and Measures - In some districts of the United Kingdom, as well as in provincial districts of other countries old local and customary denominations of weights and measures are still to be found in use, although their use may have been prohibited by law. So powerful is custom with the people. [Report of the Select Committee 1892 and other later sources] " It does not provide any examples of the old UK local units, but does mention that, in 1900, it had been necessary to make a regulation prohibiting the continued presence in school books of the old local customary units.
  5. Thinking about it, I think that, because ordinary lime solidifies by reacting with atmospheric carbon doxide, it would probably be satisfactory when used with porous bricks: ordinary bricks are quite permeable to water vapour - look up " interstitial condensation" - so carbon dioxide would have no problem with reaching internal mortar to react with it, given enough time. Hydraulic lime would be needed for masonry or engineering bricks, or damp under ground / under water constructions where the mortar in the interior would have no access to the carbon dioxide essental for its hardening, or where fast setting for early strength was needed. The soft mortar examples given in the EB article relate to impervious stone, not porous brick.
  6. Just came across this old thread. Rechargeable HT batteries did exist pre-war, but as can be seen from the accompanying extract from a book on accumulator charging published in 1941 (Accumulator Charging, Maintenance and Repair, by W. S. Ibbetson) they were almost extinct by then, having been largely superseded by dry batteries. They had cells arranged in groups of 5 or 6 (10V or 12 V). The groups were connected in series to operate a radio, and in parallel for charging, so could well have been charged on a boat that had a 12V dynamo. Few people nowadays seem to appreciate that such things existed, including members of a vintage wireless forum I subscribe to, so it's not surprising they have not been mentioned here. They are as rare as hens' teeth today. Apparently some versions had a special multi-pin plug that connected the cell groups in series when inserted one way, and parallel the other way. I believe that in the pre-war period, no radio licence was required for a radio that was powered only by its internal batteries. In the 1980's Vidor were still manufacturing dry HT batteries, including the "Winner", for industrial and military customers, but were not offered for sale to ordinary consumers, no doubt due to lack of demand.
  7. I didn't bother scanning the last part of the EB article as it is only two lines that complete the sentence about the USA. However, on reviewing it, I notice that the article does end with four lines of references. As these might be of interest to those involved in conservation who might need further information on Victorian building practices, here is the final passage of the article: "(The principal seat of manufacture is Coplay, Pa, where the first ) American Portland cement was manufactured in 1874 by Mr. David O. Saylor. The chief works of reference on this subject are G. R. Burnell, Limes, Cements, Mortars; Rivington, Notes on Building Construction; F. W. Taylor and S. E. Thompson, A Treatise on Concrete, Plain and Reinforced. " When things get back to normal, it should be possible for your public library to get copies of these books from the British Library. I have borrowed copies of Victorian books in this way in the past, although a fee is normally payable these days.
  8. Third attempt with JPG files derived from camera: previous ones were from flat bed scanner.
  9. Thanks for the info, nice to know that hydraulic lime is indeed still available. I guess the high price reflects the scarcity of the remaining natural deposits. Second attempt at posting attachments. Still no joy, attached 3 files in GIF format at under 600k each, no error messages, but nothing showing up on my phone screen.
  10. Here's some info about the types of mortar that were being used when the 11th edition (1910-11) of the "Encyclopaedia Brittannica" was written. It appears that, for lime:sand mortar, the type of lime used was so-called "eminently hydraulic lime", which could produce strong mortars that would set properly. Examples are given of old, evidently non-hydraulic, lime mortars that had been revealed during demolition, which had not set after a couple of hundred years. If eminently hydralic lime was not available, it was necessary to include a proportion of portland cement in the mix to obtain mortars that would set. The attached extract from the 1976 edition of the government's Property Serices Agency [PSA] leaflet No 16 indicates that, by 45 years ago, eminently hydraulic limes had become virtually unobtainable, and I don't suppose the supply situation has improved today. Unless supplies of the eminently hydraulic lime that used to make satisfactory lime:sand mortar a hundred or more years ago are in fact still available, a cement: lime: sand mixture would have to be used nowadays to produce a mortar with a mechanical strength comparable with the original lime mortar: a mortar consisting only of modern lime and sand is unlikely to set properly. I normally use a 1:1:6 cement:lime:sand mix for bricklaying. Mortar without lime is too harsh, as well as being too strong. The inclusion of lime yields a mortar that is almost white when dry, very different in appearance from the grey colour of 1:3 cement: sand mortar used for pointing. I should point out that I am not a professional builder, but when I needed to do some diy brickwork in my first house many years ago, and having no money to pay a builder, I read up on the subject in text books written for the trade, as well as the excellent seres of leaflets on good building practice published by the PSA and the Building Research Establishment. They used to be available from HMSO at very reasonable prices before everything got privatised. Ps the attachments don't seem to have attached. I will try again tomorrow.
  11. Thanks for the corrected link, a very interesting collection.
  12. When I first got interested in photography, circa 1960, I read all the books on the subject in my school and local public libraries. Most had been published in the early 1950's, probably as revisions of pre-war editions, and pretty well all started with a discussion of the different types of film. I vividly remember one in the school library that had a frontispiece with four identical views of a flower and fruit arrangement which included the aforementioned bowl of daffodils and some red apples and tomatoes. One was on colour, one in "Ordinary" film, one in Ortho, and one in Pan. It really brought home the differences in colour rendering of the different film types. Probably of practical use at the time, as I understand that many keen amateurs were still using plate cameras (for which sheet film adaptors were readily available) in the immediate post-war period when both Ordinary and Ortho sheet films and plates were still readily available. These days, few people seem to be aware of the different properties of the old black and white films, which is why I thought it might be useful to mention it.
  13. Something that needs to be borne in mind when considering old photos is that the use of panchromatic black and white film did not become universal until the mid-1950's. In Victorian times, film was only sensitive to blue, so people's lips were black, and the leaves and trumpet of a daffodil in a dark blue bowl would look black and the blue bowl would be white. By around 1900, orthochromatic films sensitive to blue and green, and panchromatic films sensitive to all colours had became available, but the high cost of the pan films meant that ortho was the usual choice in the first half of the 20th century. An ortho film will render the daffodil and vase in approximately correct tones, but will still give people black lips. Kodak's popular "Verichrome" roll film was ortho until the mid-1950's, when it was replaced by "Verichrome Pan". In the late 1980's I was experimenting taking photos of model trains to make them look like the real thing. I have an old camera that takes sheet film, and was able to buy a box of Ilford Ortho sheet film to experiment with. These days I would shoot in colour in digital, and then use an image editing program to remove the red content for pre-war ortho, and remove red and green for Victorian, simulations before converting to monochrome.
  14. There would have been no problem with making plates, the problem was the non-availability of plastic film base, both the nitrate used for 35mm cine prints, and the safety film for cine camera film, roll films, the 4" x 5" sheet films then widely used by press photographers, and the large format sheet films used in aerial reconnaisance cameras. Film base was simply not being manufactured in the UK. The rather lengthy document at the following link lists all the stuff supplied to the UK under lend-lease. It includes miles of film and film base (as well as thousands of pigeons!). http://ibiblio.org/hyperwar/USA/ref/LL-Ship/LL-Ship-5.html
  15. A relative who works for Ford, tells me that most electric cars seem to have been bought as second cars, used for short journeys, rather as replacements for the main vehicle. Certainly all the accounts of actual long distance trips that have appeared in the motoring press in the past couple of months have not been calculated to encourage changing to pure electric, quite the opposite! While there are now automotive batteries that can be charged rapidly, you can only make two consecutive rapid charges without irreversibly damaging the battery. Ford have just released a video of their electric Mustang. To facilitate rapid charge, the battery has had to be provided with a refrigeration unit to keep the temperature down, another thing that reduces the effective charging efficiency. My own understanding of battery technology, wearing my hat as a retired former professional electrical engineer, is that there is normally a trade- off between rate of charge and charging efficiency, meaning that the faster the charge, the lower the proportion of energy put in that can be taken out again. Likewise, local battery storage to top up the grid will always involve some loss of energy due to the double conversion. However, the main problem with the grid seems to be that the increasing proportion of electricity from renewable sources is affecting the frequency stability of the grid. You used to be able to rely on a synchronous-motored mains electric clock to show the correct time to within a few seconds: these days mine can vary by at least 30 seconds either way relative to the Greenwich time pips of Radio 4 FM. With the possibly sole exception of hydro-electricity, renewable sources either generate power at DC (solar), or at a non-synchronous frequency (wind). The grid has traditionally relied on the mechanical inertia of massive rotating generators to act as an electrical flywheel to keep the grid frequency stable: the electronic DC-AC and AC -DC- AC convertors used to convert solar and wind power to 50Hz, rely on the grid as the reference frequency for their final AC conversion stages. There was a massive blackout a few months ago when one large renewable source tripped, causing several other renewable generators to trip because the remaining conventional generators were unable to maintain the frequency within the specified limits. As far as I know, a solution to this problem, which has been known about for many years, is still awaited. I don't own a boat myself, but have taken canal holidays on average every other year since 1976. To me, one of the joys of canal holidays has been the ability to moor up at remote locations, enjoying the peace and quiet of the countryside, and watching the sun go down over the fields. The idea of having a network of charging stations at marinas and the like would be akin to hiring a camper van for a touring holiday and having to spend each night at a motorway service area.
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