November 14, 2014

Duncan MacKinnon

, the stylographic fountain pen and its inventor.

“DUNCAN MACKINNON, The Canadian druggist who invented the fountain pen”,
from ProQuest Historical Newspapers, “The Globe and Mail (1844-2011)”,
The Globe, Apr 11, 1914, in the “Saturday Magazine Section”, p.2,
as far as I know, the only known photograph of MacKinnon.

        Here’s an article from The Toronto Globe about Duncan MacKinnon, and a letter to the editor about the article, both of which can be viewed on ProQuest Historical Newspapers, “The Globe and Mail (1844-2011)”.  I can’t post links to the actual newspaper because it is on a website that requires a login with a host library.  Luckily the website has alliances with various public and university libraries, and the newspaper can be viewed at any of them.  I got a copy of the article from microfilm in the 1990s, but I recently reviewed the article on ProQuest at the university library here in my city.  The article was published in The Globe on Apr 11, 1914, in the “Saturday Magazine Section”, on p.2, and the letter was printed on Apr 17, 1914, p.6.  The pen is called a “fountain pen” throughout the article and the letter, even though it should more rightly be called a “stylographic pen”, and it’s the first successful pen that they’re talking about, not thee first pen.  The article is titled, “The Fountain Pen And Its Inventor”.  I wonder what the occasion was.

The Fountain Pen And Its Inventor [sic, Stylographic Pen].
        How a Canadian druggist living in Stratford, Ontario, was induced to try his hand at devising a fluid pencil, and how he finally succeeded in perfecting a useful commercial article.
        Books of reference, even dictionaries, name and describe the fountain pen, but in such a way as if it had been the product of spontaneous creation.  None of the writers seem to know the name of its inventor.  Watt, Morse, Howe, Bell, and other names of inventors and discoverers are household words, but no one apparently is familiar with the name of the inventor of the fountain pen.  This can scarcely he said of the inventor of any other instrument of equal utility.  Yet the personal element is most interesting in all spheres of human action.  The fountain pen is now made by scores of competing manufacturers the world over, and the business has risen into millions [of dollars].  All since [1875], when patents were issued
to the inventor at Ottawa [and London,] and [in 1876 at] Washington.
        Born in York County.
        Duncan MacKinnon was born in the township of Vaughan, county of York, Ontario, in 1838, and died in 1882.  He received a liberal education in his native county.  After teaching school for a short time he took up pharmacy, and the year 1874 found him the proprietor of a drug store In the city of Stratford.
        About this time he read a paragraph in The Scientific American asking some inventive genius of the world to produce a “fluid pencil”, that is, a writing instrument much like a lead pencil, substituting ink for the lead.  Mr. MacKinnon was at once seized with the importance of the suggestion and was soon at work, using the metal penholders of the time for his experiments.
        No attempt will here be made at describing details, nor the many difficulties encountered before the invention was put on the market.  A few facts alone In this connection will be noticed.  The chief difficulty lay in securing control of the ink-flow.  This was finally accomplished by putting an air tube in the centre of the fountain.  This was, and is to-day, the most essential part of the mechanism.  Without it there would have been no fountain pen.  Before final results were reached Mr. MacKinnon made trips to various cities in search of skilled artists, including Providence, New York, Philadelphia, and Cincinnati.
        Difficulties Overcome.
        The pen was first made in soft metal.  This experiment failed, for the ink corroded the metal, and the points soon wore off.  Hard rubber was next chosen and proved so successful that it is still the material used.  There was still one difficulty to overcome, and that was to secure a hard metal point.  This, too, was finally accomplished by the use of iridium, the hardest of all metals, and with which the gold pens now attached to the fountain are tipped.
        It will be noticed that what the inventor kept steadily in view was the production of a “fluid pencil”.  He had no thought for attaching an ordinary pen to the fountain.  This fluid pencil, although still in the market, is not suited to fine penmanship.  Others soon discovered this. Cross of Providence, R. I., was the inventors manufacturer.  This gentleman conceived the idea of substituting an ordinary pen for the point [sic, substituting a spring for the weighted needle], and proceeded to manufacture and sell, regardless of business ethics or possible infringement, calling his. pen the stylographic.  Other makers, the world over, followed in quick succession.  The rest is present-day history.
        Like many other inventors, Mr. MacKinnon ploughed the field and sowed the seed, but others reaped the harvest.  [More georgic metaphors.]
        First Described In The Globe.
        The Globe was the first Canadian paper to publish an account of Mr. MacKinnon’s invention.  That was in 1878 [?].  In the United States, The Scientific American was the first to publish a description of the new writing instrument [in an article on Aug 10, 1878, p.80].  The writer [also] has before him [an article from] the last-named journal [on] the date April 24, 1880[, p.261].  The description is somewhat lengthy and is accompanied by an illustration of “The MacKinnon Fountain Pen”.

        And here’s the letter by Angus G. MacKinnon to The Toronto Globe, Apr 17, 1914, p.6.
The Inventor Of Fountain Pens
[sic, Stylographic Pens].
        To the Editor of the Globe; I thank you for the article on the invention of the fountain pen.  It is excellent and gives a just presentiment of my brother’s claim to be the inventor.  I am glad to think that, after having been forgotten so many years, his great accomplishment should be recognized and his memory honored.  He was a man who in his life was liked and respected for his social qualities and business ability, and in death he is remembered for the good he did.  Had he entered into a partnership with Cross & Son he would likely have had a greater return for his labor and expense. Several years of impaired health preceding his death were possibly not without influence on the outcome.  There are slight inaccuracies or discrepancies in the article.  Duncan MacKinnon was not born in Vaughan, but in Markham, in the old homestead near Unionville, one-quarter mile distant [
just north of Toronto].  A few years of his boyhood were spent in Vaughan and a short time later, but nearly all his work was done in Markham until he went to Western Ontario at the end of 1868.  Your date of the first Globe article on the pen [1878 ?] does not agree with the date written on the clipping I have.  I can hardly believe that my date is wrong.  There may have been two Globe articles.  [He didn’t give the date, but its probably the next one below, from 1876, or they may have confused it with the Sci. Am. article below, from 1878.]
        Angus G. MacKinnon, Sonya, Ont., April 13.

        Here’s the first article about the MacKinnon stylo in The Toronto Globe, Mar 9, 1876, p.4.
The MacKinnon Pen.
An Important And Useful Invention.
        We have been shown and have had the privilege of testing one of the most ingenious and useful inventions brought under our notice for a long time.  The invention is called “The MacKinnon Pen”, and its name sufficiently indicates to what use it is applied.  This novel instrument in outward appearance much resembles an ordinary gold pencil case.  It is made of metal, and is double plated with gold both inside and out to prevent corrosion by the ink.  It is composed of a barrel and a point.  The barrel has a small air tube extending from the top down to where the point is united to the barrel by means of a screw.  The point is composed of a valve chamber and slender perforated point, in which plays a valve having attached to it a needle.  The ink is readily placed in the barrel by a little instrument called the dropper.  To make the pen ready for use, all that is necessary is to let in the air, which is done by giving a turn to a screw-cap placed on the upper end.  It will thus be seen that the instrument works on a hydro-pneumatic principle.  Of course we are unable to give more than a general idea of this elegant, ingenious, and useful invention.
        The merits of this pen over all other pens and pencils are numerous, and must be obvious to all who examine and use it.  First, it is an inkstand, pen, and pencil all combined in one, and, in travelling, carrying of all these is obviated, and one is at all times armed for the purpose of writing, as the instrument may be carried in the pocket like a pencil; it does away completely with all blotting, soiling of fingers, and sharpening of pencils; it economizes time by obviating the necessity for constantly dipping for ink; the point being smooth, round, and without a split, it glides along on the paper so easily that no pressure whatever is required, and the writer has simply to guide itthus enabling him to write more rapidly and with greater ease than it is possible to do with any other pen or pencil; it writes with ease on the roughest paper, and for the purpose of ruling must excel everything else, since blotting is rendered impossible.  To put it in brief, the merits of The MacKinnon Pen are, that it is always ready for use, at all times and placesthat it is perfectly clean; that it economizes time, and enables us to do more work with less labor than we have ever before been able to do.  These advantages should make it a welcome boon to all who use a pen.  We have no doubt this new pen is destined to displace the ordinary pen to a very large extent, and that the ingenious inventor will be amply rewarded for the industry and perseverance[,] which he has bestowed upon his invention.
        The inventor is Mr. Duncan MacKinnon, of Stratford, Ontario.  About five years ago, Mr. MacKinnon read in The Globe an article taken from the Pall Mall Gazette, in which the writer had adverted to some of the drawbacks to the ordinary pen and lead-pencil, and called attention to the fact that while improvements had been made, and were constantly being made, in every other department, no improvement worthy of the name had been made for ages in writing instruments.  After calling attention to these facts[,] the writer proceeded to call upon the scientific world to produce an indelible pencil that would supersede both the pen and pencil in common use.  After some thought and ineffectual experiments with a view to produce such a pencil, Mr. MacKinnon turned his attention to an endeavour to construct an instrument which, though using ink as the marking agent, would yet possess all the advantages demanded by the writer in the article referred to.  He was not long in discovering the general principles of such an instrument, and had one made, which, though necessarily imperfect, satisfied him that his object was attainable; but, engaged in [other] business, he was unable to give the matter much attention until a little over a year ago, when he began to apply himself to its perfection.  After many discouragements, chiefly of a mechanical nature, he has at length been able to produce his invention in the shape above described.  Although simple enough in some respects, yet it is an instrument calling for the very finest of workmanship, and it was not until Mr. MacKinnon fell in with Messrs. Cross & Son, pen and pencil case manufacturers, Providence, R. I., that he was able to obtain a sample complete and satisfactory in all its parts.  The specimen in our hands is a highly finished and beautiful looking article, and will make a handsome appendage, to say nothing of its usefulness, to the writing desk, either lady’s or gentleman’s.
        Mr. MacKinnon has obtained letters patent for his invention in Canada, the United States, and Great Britain.

        Here’s the second article about the MacKinnon stylograph in
Sci. Am., Aug 10, 1878, p.80.
Fountain Pens [sic, Stylographic Pens].
        For several days we have had in use in our office examples of the MacKinnon Fountain Pen, and find it to be a very serviceable and effective instrument.  This is a handsome looking pen, with a hollow handle, in which a supply of ink is carried, and the fluid flows from the point in the act of writing.  The necessity of an inkstand is thus avoided.  One of the difficulties heretofore with pens of this character has been to insure a free and certain delivery of the ink, and also to bring the instrument within the compass and weight of an ordinary pen.  The inventor seems to have admirably succeeded in the example before us.  The ink flows with certainty, and there is no scratching as with the ordinary pen; it writes with facility on either smooth or rough paper: writes even more smoothly than a lead pencil; may be carried in the pocket; is always ready for use; there is no spilling or blotting of ink.  The construction is simple, durable, and the action effective.  One filling lasts a week or more, according to the extent of use.  These are some of the qualities that our use of the pen so far has seemed to demonstrate; and which made us think that whoever supplies himself with a MacKinnon Pen will possess a good thing.  The sole agency is at No. 21 Park Row, New York City.

        Here’s another article about the MacKinnon stylograph in Sci. Am.,
Apr 24, 1880, p.261.
A New Writing Instrument.

        No one using a pen constantly, or even for any considerable portion of the time, can fail to feel the want of something better adapted to ordinary writing than steel or gold pens.  The constant dipping, which not only takes time, but is fatiguing; the liability of blotting, and in the case of steel pens, their failure soon after they get into good condition for use, are all serious objections which existed from the first days of pens and ink until the invention of the complete little instrument shown in the annexed engravings.  Fig. 1 shows the MacKinnon fountain pen in actual use, Fig. 2 is a sectional view showing the internal construction; and Fig. 3 shows the pen about to be closed to be carried in the pocket or laid upon the desk.  In general outline it resembles many of the penholders or pencils now in use.  The handle is a tube which holds ordinary writing or copying ink.  The writing point is conical and terminates in a graceful tube of gold tipped with iridium, polished smooth as glass.  Through a fine aperature drilled through the iridium on the point, the ink flows at the slightest touch on any surface, and it is so constructed that as soon as the pressure of writing is removed, the ink instantly ceases to flow.
        With one filling this pen is capable of writing from seventy to eighty pages of foolscap.  It can never blot, and when not in use it is closed perfectly tight, so that the ink cannot thicken or dry.  Any good ink may be used, and the ink reservoir is readily filled by means of a small glass filler accompanying each pen.  The MacKinnon pen is not only of the greatest service to those who write continuously, but it is a very necessary article for canvassers and others who desire to make a permanent record, and to whom it is a serious inconvenience to carry the ordinary writing materials.
        This pen has several advantages over its competitors, the most important of which are:  The improved valve, which is operated by a weight instead of [a] spring, making be action more reliable and rendering it less likely to get out of order.  The writing point is a circle of iridium, one of the hardest of substances known, and is perforated with s fine, tapering hole, through which the ink flows in writing.  The patent for perforating iridium is controlled by the MacKinnon Pen Company, 200 Broadway, New York, and is applied exclusively to their make of pens.
        These pens have been in use in the Scientific American office for over a year, and have given good satisfaction.

        And just for good measure, here’s the article introducing the Livermore stylograph, which used the MacKinnon patent, in
Sci. Am., June 26, 1880, p.403.
Improved Stylographic Pen.
        For over two years fountain pens or ink pencils have been sold in this and other countries, and thousands have found them to be a very useful instrument.  During this time many defects have been noticed and efforts made to overcome them, resulting at least in the production of the newest and latest pen of this kind, which was patented March 9, 1880.
        The pen consists of an ink holder of vulcanized rubber, ornamented and beautifully mounted.  The ink is conveyed by capillary attraction to the tubular point, containing a solid iridium-pointed needle.  It combines all the advantages of pencil and pen, and is a great saver of both time and patience.
        Fig. 1 shows the pen complete in its new form.  Fig. 2 represents the point section removed and ready for filling.  Fig. 3 shows the new and late improvements, the duplex, interchangeable point section.  The advantages of these improvements are at once apparent.  If by any accident the pen point should break down, a new one could be obtained at a small cost.  Two points can be had with each pen for fine and coarse writing.  The needle by being detached from the air tube, D, cannot become bent or broken while filling the pen, but is always protected by the section, B.  The new pen has the delicate spring on the end of the needle completely covered, thus effectually [effectively] preventing oxidation, a source of constant annoyance in those of earlier make.
        Further information may be obtained from the Stylographic Pen Company, office No. 169 Broadway, Rm.13, New York.

Canadian patent no. 4,809, p.7, May 1, 1875.

George Kovalenko.


Addendum 1, Nov 16, 2014, and Jan 6, 2015.
Some of these items were among the ones I submitted to The Pennant, Spr/Sum 1995, pp.6-8.
Also see my blog posts “MacKinnon v. Cross?” and “MacKinnon v. Cross!”.

Addendum 2, Aug 1, 2016.

The following information was found by Doug Stapleton, a genealogical researcher in Sarnia, Ont.
        “While researching Duncan MacKinnon, I found his surname, and that of his brother Angus, misspelled as “McKinnon” several times.  I have been unable to find where he was born, or the names of other family members.  I did find both brothers in the 1871 Census for Sarnia in Lambton Co.  Angus McKinnon, age 37, was listed as a physician, Sarah his wife 32, Agnes 7, Norman 5, Flora 1, and Duncan 32, druggist.
        “The 1880 US Census was undertaken in June, and I next found them in Adrian, Lenawee County, Michigan.  Adrian is 30 miles south of Ann Arbor and was the county seat for Lenawee.  Angus age 46, physician, Sarah 41, Flora 10, Jessie 2 and Duncan 41, brother of the head of household, druggist.  During further online research, I found that both Norman and Agnes died in the mid-1870s.  The 1881 Canadian Census was undertaken in April, and although I have searched several spellings of the MacKinnon surname in Lambton County, I have not found them.  They must have moved to Alvinston after April 1881, and thus would not have been enumerated.  And continuing with the 1891 Canadian Census for Lambton County, I found Angus age 55, a physician and surgeon in the town of Alvinston, Sarah 48, Flora 20, Jesse 13, but no trace of Duncan.  I also didn’t find any info online connecting him to Stratford.
        “I did a search of deaths and found that Duncan McKinnon died on March 18, 1882, age 43, in Alvinston, listed as a druggist.  His brother was listed as his physician and informant.  His death was due to chronic pneumonia, and he had been suffering for 6 years with this illness.
        “I visited Lambton County Archives and found that he is buried in the Alvinston Cemetery in Brooke Township.  His brother and family are also buried in the same row.”
        I always had unspoken reservations about the death certificate shown in The Pennant,
Spr/Sum 1995.  The middle initial “H.”, the age “49”, his marital status “married”, the number of years in the US “9”, and the occupation “carpenter” are all wrong.  And he caught his pneumonia six years before in Providence, R. I., while dealing with Cross, and he never got over it!  This new death certificate vindicates my suspicion.  It made no sense that he was still in New York in 1882, when he was no longer a principal in the company he started.  And nine years before his death, he was still a druggist in Stratford, not in the US.  He was in Stratford for only a few years in the 1870s, according to an article in the Stratford Beacon, Mar 1, 1873, and an ad and a listing in the Stratford Business Directory in 1876, all of which were part of the original packet I submitted to The Pennant, but which weren’t published.  As well, his patents in 1879 and 1880 place him in Stratford and Lucknow, Ontario.  So, I went back and checked my copy of the death certificate, and the surname there was actually spelled “McKinnion”, twice!  This death certificate is for a totally different Canadian, and the surname was altered, or “corrected”, by the editor of The Pennant, to try to make it fit.  We are indebted to Doug Stapleton for finding the actual death certificate of Duncan MacKinnon, thus helping to clear up and correct this glaring mistake in the pen history record.  By the way, I got the packet of information that was published in The Pennant from the Stratford Perth Archives, so they should be informed that they had the wrong death certificate in their files all along.
        I am still waiting for and hoping to get these crucial bits of the official record.
        1. Duncan MacKinnon was born in Unionville, near Markham, just north of Toronto, so the 1861, 1851, and 1841 Canadian censuses for Unionville and Markham still need to be checked.
        2. The new death info is the best part!  If it is from a death certificate, I am hoping to get a photocopy, or digital copy of the certificate, so that I can post a link to the image here to correct the death certificate in The Pennant.
        3. I am also hoping to get a photo of the headstones in the
Alvinston Cemetery in Brooke Township, not just his, but those of his brother and the rest of the family, the whole row.  All the birth and death dates should literally be carved in stone there.
        By the way, here’s the information about Duncan MacKinnon’s birthplace in Unionville, Ont., near Markham, Ont.

Duncan MacKinnon was born in Markham [ca. 1839], in the old homestead near Unionville, one-quarter mile distant, in the letter by his brother Angus G. MacKinnon to The Toronto Globe, Apr 17, 1914, p.6.
And I added the information about Duncan MacKinnon as a penmaker to the Wikipedia page for the city of Stratford, Ont., in the “Notable past and present residents” section.
Duncan MacKinnon was a druggist in Stratford, 1873-76, and a penmaker, the inventor of the stylographic fountain pen in 1875, cf. the article in The Toronto Globe, Apr 11, 1914, in the “Saturday Magazine Section”, on p.2.

Addendum 3, Aug 11, 2016.

The MacKinnon pen was still being reviewed, and favorably, as late as 1885, as shown by this article in The Engineer, Mar 27, 1885, p.250, even after the failure of the company in March 1884.
The MacKinnon Pen
        Although the pen is as old as the sword or the plough, its original form is still retained; but the material of which it is made is now drawn chiefly from the mineral instead of from the vegetable kingdom.  About the year 1875, Duncan MacKinnon, a druggist of Stratford, Canada, read a statement in the Scientific American to the effect that he who would devise an ink-writing instrument, as convenient as the lead pencil, would achieve both fame and fortune.  This stimulated his inventive powers, and abandoning the usual form of split nib, he started from the stylus of the ancients.  In a couple of years he had produced an instrument which, though far from perfect, was welcomed in the United States, and, after a year’s constant use, was stated by the above-named journal to have “given good satisfaction”, while the Science and Art Committee of the Franklin Institute also reported favourably on the invention.  But, though the correct principle had been attained, the practical difficulties of manufacture were far from being surmounted.  The metal cases were too heavy, besides being liable to corrosion by acid inks; and the platinum points wore away quickly.  Ultimately, vulcanized india-rubber was adopted for the case, being both light and proof against corrosion.  Glass was tried for the points, but, though hard enough, was found too brittle.  Iridium answered the purpose admirably; but it took six and a half hours to drill the first point with a hole too large for the needle, besides wearing out a 10-dollar diamond drill.  Later on, a Swiss succeeded in drilling two small holes of the required size, and hoped to accomplish six or eight holes a day.  The process of drilling was secured by patents; and the successive improvements in the pen itself were patented in [Canada], the United States, Great Britain, and other countries.  The MacKinnon pen now became a fact, and its success induced pencil-case makers to imitate it as closely as possible; but the points were made with a platinum alloy of uncertain hardness, the durability of which could not be depended upon.  The MacKinnon is chiefly distinguished from other forms of stylographic pen by the iridium point, which is practically unwearable.
       The needle which regulates the flow of ink at the orifice is also controlled mainly by a weight, forming a clack valve, which is lifted by pressure of the pen on the paper, the needle projecting slightly beyond the point when there is no contact with the paper.  A weak spiral spring is, however, added probably to overcome the friction and inertia of so slight a weight.  The annexed
views, partly in section, will assist in understanding the construction and working of the pen, which is really an ingenious piece of mechanism.  The tube or holder G is filled with ink, which should be of good quality, and especially of uniform composition, but not too thin, as might have been supposed the best.  The orifice is closed by screwing in the needle chamber D, a slightly enlarged detail of which is shown in section.  Inside the holder is the tubular air chamber F, with its outlet E, and an inlet at I, the open end of the tube being closed by the cap H; but a flat side is formed upon the screw, for admitting air on the cap being unscrewed.  As the ink in the holder is used, the air, entering to supply its place, maintains an even feed and flow.  C is the hollow iridium point, and E the needle, made of gold and tipped with iridium, that works therein, breaking up air bubbles and displacing minute extraneous particles that would otherwise collect at the point and intercept the flow of ink.  A is the cover for protecting the point when the pen is not in use, and which, for convenience, is placed on the projection at the other end when the pen is being used.  In the newest form of MacKinnon pen this cap is made longer and of the same diameter as the holderas shown in the second viewso as to add to its length, a great convenience in writing, besides giving the pen s simpler and more business-like appearance.  The inside of the cap is also provided with an india-rubber cushion, which completely closes the point when not in use.
        This pen is really a very delicate instrument, so constructed as to withstand ordinary rough usage.  Various hypotheses of a very ingenious character have been published as explanations of the working of the pen; but it is quite clear that the idea that capillary attraction would prevent the flow of the ink down the very small space between the needle and the very small hole in which it fits is erroneous.  When in use, some of the ink is rubbed off the point to the paper; and the molecular cohesion of the fluid is sufficient to cause the flow of more ink to the point, this flow being permitted by the air supply from above, and capillarity really helping in the work of drawing the ink along the tiny channel allowed it.

Addendum 4, Aug 14, 2016.
Here are some more of the crucial bits of the official record found by Doug Stapleton.
        “The 1842 Assessment, not a census, lists only the head of the household, so until I discover his father’s name, I can’t do much else.
        “I searched the 1851 Census for York Co., Ont., which includes Markham and Unionville, and if the birth date of 1839 is correct for Duncan, I should have found a family group with his listing at age 11-12, and Angus 16-17, but with no luck.
        “The 1861 Census for Vaughan, York Co., lists Duncan McKinnon, 22, a school teacher living with Hugh age 24, farmer, Donald 23, and five other children ages 19 to 6, probably his brothers and sisters, and Flora McKinnon age 48 born in Scotland, housekeeper.  Elsewhere in this census district there is an Angus McKinnon age 28, a school teacher living on his own.
        “Here is the death certificate from the “Ontario Deaths 1869-1937”, p.469, record
no. 008451, County of Lambton, Division of Alvinston. “Duncan McKinnon [sic], 18 March 1882, Male, age 43, Druggist, born in Ontario, died of chronic pneumonia, duration of illness 6 years, his physician and informant Dr. Angus Mackinnon [sic] MD of Alvinston, death registered on Mar 27, 1882, religion Presbyterian”, estimated birth year 1839[?].
        “I visited the Alvinston Cemetery and took a photo of Duncan MacKinnon’s
headstone.  He is buried in Range 13, Lot 10.  Besides Duncan’s headstone, the only other MacKinnons were Aggie and Norman, children of Dr. Angus and Sarah MacKinnon.
        “I went back to the Lambton County Archives and a wonderful archivist named Patricia McEvoy helped me find information contained in an Alvinston book published as a centenary project, 1880-1980.  In it I found information about Dr. Angus MacKinnon, including, “In 1881, Dr. McKinnon [sic] opened a medical practice.  He gave devoted service for 20 years, then retired to Los Angeles”.  I found him in the 1910 US census for San Gabriel, Los Angeles, indicating that he and his wife immigrated to the US in 1902.  Angus MacKinnon died on Aug 3, 1918.  The 1920 US Census found Sarah living in Glendale, Los Angeles, with her daughter Jessie and son-in-law George Lockwood, a high school teacher.  I have created a memorial for Duncan in the Alvinston Cemetery in a Genealogy website called,
#168225642.  I used info for the bio from parts of your blog, The Globe article, and Angus’s letter to the editor.  I’ve also included the obituary and the photo of the headstone.  I also discovered that someone took a photo of Angus’s headstone in California, memorial #145376726.  His wife Sarah, memorial #145376727, died on Jan 24, 1926. [And here are their daughter Jessie and her husband George, memorials #85453297 and  #85453290, and their daughter Flora, memorial #145376728.  It looks like Angus and Flora might have been victims of the Spanish flu, dying just days apart in August 1918.]
        “Patricia McEvoy also helped me find Duncan MacKinnon’s obituary, which appeared in the Watford & Alvinston Guide-News, Mar 24, 1882, p.5.  “Mr. Duncan MacKinnon, brother of Dr. MacKinnon, who had been ill for some time, died on Saturday last, and his remains were interred on Monday of this week.  Mr. MacKinnon was not very extensively known in this neighbourhood.  He was a gentleman of culture and refinement”.”