*Mathematical Messenger*

**8**(5) (1896), 20-24.

I was born in Berks County, Pennsylvania, on the 10th of March, 1818. In 1820, my father removed his family, consisting of my mother, three brothers, one sister and myself, to Westmoreland County, Pennsylvania. and in 1824 we again removed to Columbiana County, Ohio, where I worked, with my father, and brothers on a farm until the fall of 1836, attending school occasionally when I could be spared from work. Up to this time I had attended school, at intervals, in all, about 18 months, and had learned to read and write and "cypher". Neither Grammar nor Geography was taught in any school I ever attended. But as it was believed that I was expert in Arithmetic, I had no difficulty in getting an engagement to teach a school, and taught my first school in the winter of 1836-7. In the spring of 1837, as I was then 19 years old, at which age my father relinquished all authority over his boys, and permitted us to pursue whatever course we preferred, by mutual agreement I divided with my father the proceeds of my winter's school (as they were earned before I was 19 years old), gave him half and retained one-half myself, and, soon after, apprenticed myself for two years to learn the trade of a mill wright, with the understanding that I would not work at the trade during winter but would teach school.

During the winter of l837-8 I taught the same school that I taught the preceding winter, and, by some means, I do not now remember how, or where, I obtained a copy of John Hamilton Moore's Navigation, and a copy of Ostrander's Astronomy, which contained the necessary tables for calculating eclipses of the sun and moon. With these books I was much interested, and during this winter, and throughout the period of my apprenticeship, I devoted all the spare time I could command, both winter and summer, to the study of these two books; and though I had not yet seen a work on Geometry, I became quite expert in Plane Trigonometry, and learned to calculate and project both solar and lunar eclipses with considerable facility. The term of my apprenticeship having expired, I spent the winter of 1838-9 working at my trade, in St Charles County, Missouri, but returned to Ohio and worked at my trade during the summer of 1839. In the fall of 1839 I again engaged to teach a school during the winter of 1839-40. Up to this time I had never seen a treatise on Algebra, nor had I ever conversed with an algebraist. Before I commenced my school, however. one of my brothers had come across, and bought, a copy of Bridge's Algebra, but could not understand it, he said, and gave it to me.

Instead of boarding around with the scholars during this winter, as was then frequently the custom, I boarded at a country tavern, and had a private room with fire and lights. After getting my school fairly started, I determined that I would find out what merit, or utility, there was in Algebra, and for that purpose I set apart two hours of each night for the study of Algebra. I shut myself up in my room at 8 o'clock each evening, excluding all company, and studied my algebra till 10 o'clock, at which time I generally went to bed, not always to sleep, however, as I frequently spent hours, after I had gone to bed, in thinking over some difficulty that I had encountered in my study. In five weeks, by pursuing this course. I had gone through this book, and solved all the examples the book contained, and many other questions that I had before been unable to solve, but which I was able to solve readily by the use of Algebra.

At the close of my school in the spring of 1840, though I was sensible that I could apply Algebra in the solution of many questions with great advantage, yet I wished to know from conversation with an acknowledged mathematician to what extent I was an algebraist. I had never seen Abijah McLean, who lived at New Lisbon, and who had the reputation of being a great mathematician, but I determined to visit him and learn from him how much I knew and how much I had yet to learn, to become a mathematician. I accordingly selected a considerable number of what I regarded as my best solutions and took them with me and went to New Lisbon and called upon and introduced myself to Mr McLean. Of course I was embarrassed but I made out to tell him what I had done and showed him my solutions. He examined my solutions with much interest and complimented me for what I had done, but he selected one of my solutions, and it happened to be the one that I thought the most meritorious, which he undertook to criticise. He pronounced my solution unnecessarily complicated and undertook to show me how it could be improved and simplified. After working at the question for some time McLean was called away, temporarily, and turning to a mathematical student of his who was present, a Mr Dibble, he said. "Mr Dibble, work this out till I come back". Mr Dibble worked at it till McLean came back, but could make nothing out of McLean's improvement, and McLean himself, after examining it further, concluded that my method was satisfactory and perhaps the best of which the question admitted. I refer to this incident because I think it was beneficial to me; it increased my confidence in own conclusions. McLean, though 20 years my senior, was ever afterwards a warm friend of mine and a frequent correspondent until his death, which occurred some 15 years ago. It is to him I am chiefly indebted for the mathematical knowledge I have since acquired. From his library I obtained most of the mathematical books I have since studied, including Newton's Principia, Hutton's Mathematics, and Bowditch's translation of the *Mécanique Céleste*.

While I was yet an apprentice, I formed a slight acquaintance with a physician, Dr George S Metzgar, then recently from Philadelphia, a graduate of Jefferson Medical College, and who had been an office student of the then eminent Surgeon, Dr George McClellan, (father of the late General McClellan). I admired the doctor's learning and especially his ready flow of language and the ease and grace of his deportment, and, in the spring of 1840, I proposed to read medicine under his instruction for a period of two years, and support myself in the mean time by teaching school occasionally, and was accepted by him as a student of medicine. I had then more faith in medicine than I have now, and the study of medicine soon became as interesting to me as the study of mathematics had been.

After reading medicine industriously some two or three months in the spring of 1840, I was offered a summer school for a term of three months, and as I needed the proceeds, and believed that it would not interfere with my reading, I concluded to accept the offer; but I was required, in this school, to teach Grammar, and I had never studied it. I therefore bought a copy of Kirkham's Grammar, and studied it two weeks, in which time I had committed a good part of the book to memory, and as the time was near at hand when I was to commence my school, I went to New Lisbon to be examined and obtain a certificate of qualification to teach. The examiner's name I have forgotten, but he was at that time a member of the Ohio Legislature and I believe a man of fair intelligence. After making the examination, he wrote the required certificate and remarked, on handing it to me, that I was especially well qualified to teach English Grammar.

I taught my school, and I believe satisfactorily to my employers, continued my reading and taught school during each of the two succeeding winters, and in the spring of 1842, not having accumulated sufficient money to enable me to attend medical lectures, but armed with a very flattering certificate of qualification from Dr Metzgar. I went to Weston, Ohio, intending to practice medicine a couple of years and accumulate funds sufficient to enable me to attend medical lectures and graduate, after which I intended to spend my life in the practice of medicine. Instead however of accumulating money, the accumulation remained in anticipation, and instead of attending medical lectures I married my wife in the spring of 1843. And although I never abandoned the INTENTION, while I was engaged in the practice of medicine, of attending lectures and graduating as an M.D., the increasing demands upon my time and attention, arising from the care of a family of children with which I have been blessed, precluded me from doing so; and hence, though I practiced medicine as a profession, about 20 years, with, I trust, a fair degree of success, I never graduated as an M.D. And here I will say, with respect to the medical profession, that although I regard a good and intelligent physician as one of the most honourable, and most valuable members of society, yet in consequence of the ignorance and cupidity of many practitioners, and of the insane faith of the majority of mankind in the efficacy of medicine to CURE disease, I believe with Dr Holmes, that the human family would he the gainer if all medicine were thrown into the sea. During the latter period of my practice, and after I abandoned the practice of medicine, though I never made politics a study, and never aspired to a political office, I was intrusted with several local offices, including that of School Examiner, County Surveyor, County Treasurer, County Auditor, Deputy U.S. Surveyor of Colorado, and Deputy Provost Marshal of De Kalb Co., Indiana during the war.

During this period of my life, viz., a few years prior to 1860, I cooperated with Rev R Faurot, Rev James Hadsell, Mr H Fusselman, and various other citizens of Newville and vicinity, in the organization of the Newville Academy, and was elected a member of the board of trustees, and, by the board, I was elected its president and teacher of mathematics in the Academy, both of which positions I held until I resigned them in favour of Mr Faurot a couple of years later.

I removed from Dekalb Co., Indiana to this place (Des Moines, Iowa) in 1864. After my arrival here until I commenced the publication of the Analyst, my time was chiefly occupied in surveying, and since the commencement of the publication of the Analyst I have performed no other important work.

I had born to me by my wife, one son and eight daughters. My only son, and first born, died, a union soldier, in my presence, three hours after I found him, at Mitchelville. Tennessee, on the 8th day of December, 1862; and two of my daughters have also died; six are living; five married and one single.

J E HENDRICKS.

Des Moines, Iowa, June 20, 1892.

This sketch was written by Dr Hendricks, at our request, for publication in the MATHEMATICAL MESSENGER, about a year before his death, which sad event took place at his home in Des Moines, Iowa, on June 8, 1893, and we thought it best to publish it just as he penned it.

Dr Hendricks was entirely a self-taught mathematician, yet he attained a world-wide reputation as a deep thinker and a profound mathematician. His reputation was reached chiefly through his editorship of the Analyst, which was highly appreciated both in Europe and America, and for ten years, and until failing health compelled him to relinquish it, he kept it in the front rank as a journal of mathematics.

He was a steadfast friend, a devoted husband and father, indeed he was one of nature's noblemen. He was a valued contributor to many mathematical journals, among which were the Analyst, Annals of Mathematics, MATHEMATICAL MESSENGER, Mathematical Visitor, and Mathematical Magazine. Many favours did he bestow upon the Messenger and we counted him as one of our dearest and most substantial friends.

In 1865 the University of Indiana conferred upon him the honorary degree of A.M. He lived to a "ripe old age", and fell to sleep in death surrounded by his loving family. When he died really "a star had fallen", and we carefully and tenderly tied up his voluminous correspondence with us and dropped a tear in remembrance of valued friendship and in honour of his greatness and goodness of soul.

G H Harvill,

Editor and Publisher,

The Mathematical Messenger.