624 



NA 7 URE 



[October 29, 1903 



Glasgow College is full of interest, and his testimony 

 to the impulse he received from his early teacher will 

 be an enduring tribute to Nichol's memory. 



In the course of his remarks, Lord Kelvin said : — 

 Principal Story, You recall to my mind the happy 

 days of long past years, 1836, when John Pringle 

 Nichol came to be professor of astronomy in the Uni- 

 versity of Glasgow. From the time he first came 

 among us — I say among us, because I, as a child, 

 was not then a member of the university, but an in- 

 habitant of the university — when Dr. Nichol, as we 

 then called him, came among us, he became a friend 

 of my father, and that friendship lasted to the end of 

 my father's life. I may also claim that I became a 

 student of Dr. Nichol's from the time he first came to 

 Glasgow. Year after year passed, and I still re- 

 member his inspiring influence. The work on which 

 I am engaged at this day is work to which I was 

 initiated In the years 1837, 1838, and 1839, when I was 

 a child. The summer of 1840 is for me a memorable 

 summer, a year of brightness In my memory. I had 

 been for one session a student In the natural philosophy 

 class of the university conducted by Dr. Nichol. From 

 beginning to end, with the exception of a few days, 

 when my predecessor, Dr. Meikleham, began the 

 course which he could not continue on account of his 

 health, the class of natural philosophy, In the session 

 1839-40, was taught by Dr. Nichol. He came on short 

 notice to occupy the post, and he did it in a most admir- 

 able manner. I lately had the opportunity allowed me 

 by my friend and colleague, Prof. Jack, to see a manu- 

 script book of John Pringle Nichol's, a book of 

 exercises and preparations for the natural philosophy 

 class. I was greatly struck with It, and much In- 

 terested to see In black and white the preparations he 

 made for the splendid course of natural philosophy that 

 he put us through during the session 1839-40. In his 

 lectures the creative Imagination of the poet Impressed 

 youthful minds in a way that no amount of learning, 

 no amount of mathematical skill alone, no amount of 

 knowledge in science, could possibly have produced. 

 For, many years afterwards, one of the most Important 

 affairs I have ever had to do with began with what 

 I learned in the natural philosophy class In that 

 session. I remember the enthusiastic and glowing 

 terms in which our professor and teacher spoke of 

 Fourier, the great French creative mathematician who 

 founded the mathematical theory of the conduction of 

 heat. I was perfectly astonished. I remember how 

 my youthful imagination was fired with what I heard 

 from our teacher. I asked him, " Do you think I 

 could read it? " He said, " The mathematics is very 

 difficult." At the end of the session I got hold of the 

 book (" Th^orie analytlque de la Chaleur ") out of the 

 university library, and in the first half of the month of 

 May, 1840, I had, I will not say read through the book, 

 I had turned over all the pages of It. Then we started 

 out from Glasgow for Germany, the joint families of 

 my father, my brothers and sisters, and our friend 

 Dr. Nichol and Mrs. Nichol, and John Nichol and 

 Agnes Jane Nichol. The two families made together 

 a tour in Germany, and during two months or six 

 weeks in Frankfort, Mrs. Nichol and her two children 

 were with my father and his family every day whUe 

 their father went on tour to the Tyrol. Excuse me for i 

 speaking of those old times. I am afraid I have 

 trespassed on your patience. These recollections may 

 be nothing to you, although they are dear to me. 

 They are. Indeed, closely connected with the subject 

 of the present meeting. 



While we were encamped for a time in Bonn, Dr. 

 Nichol took me and my elder brother on a walking 

 tour in the volcanic region of the Elfel. We had four 

 days of intense enjoyment, and the benefit of what we 

 learned from him, and saw around us, In that interest- 

 NO. 1774. VOL. 6Z'\ 



ing region remained with my brother all his life, and 

 remains with me. 



I have to thank what I heard in the natural philo- 

 sophy class for all I did in connection with submarine 

 cables. The knowledge of Fourier was my start in 

 the theory of signalling through submarine cables, 

 which occupied a large part of my after life. The in- 

 spiring character oT Dr. Nichol's personality and his 

 bright enthusiasm lives still In my mental picture of 

 those old days. 



The old astronomical observatory — the Macfarlane 

 Observatory — was situated in the upper part of the old 

 collep-e green, or garden, as we used to call it, behind 

 the college, off the High Street. I do not suppose any 

 person here ever saw the old college green, but you have 

 all read of it in " Rob Roy," and of the duel between 

 Osbaldistone and Rashlelgh. I do not remember the 

 details of the duel, but I remember it was appointed 

 to be fought In the upper part (at least I have always 

 assumed, In my mind. It was in the upper part) of the 

 college garden of the University of Glasgow. The 

 garden was in two parts, the lower on the near side 

 of the Molendlnar, the upper on the higher ground 

 beyond the stream, which we crossed by a bridge. 

 Has any person here ever seen the Molendlnar? There 

 used to be mills on it, I assume, from the name. It 

 Is now a drain ! Before we left the old college it was 

 covered In. We had still the upper and lower green, 

 but the Molendlnar flowed unseen for many years after 

 the university left the old site. I remember In the 

 Macfarlane Observatory beautiful experiments on light 

 shown us In the most delightful way by Dr. Nichol, 

 Grimaldi's fringes by sunlight, and prisms showing 

 us splendid solar spectra, and telescopes, and 

 brilliant colours on a white screen produced by the 

 passage of polarised light through crystals. He gave 

 us firmly the wave theory of light, and Introduced us 

 to Fresnel's work. As he appreciated Fourier, so he 

 appreciated Fresnel, two of the greatest geniuses in 

 science, and fired the young imagination with the 

 beautiful discoveries of those men. In that old observ- 

 atory in the high green, and In the natural philosophy 

 class-room of the old Glasgow college, was given to 

 me the beginning of the fundamental knowledge that 

 I am most thoroughly occupied with to this very day, 

 and I am forcibly obliged to remember where and when 

 my mind was first drawn to that work which is a 

 pleasure to me, and a business to me just now, and 

 will, I hope, be so for as long as I have time to work. 

 You can imagine with how much gratitude I look 

 upon John Pringle Nichol and upon his friendship with 

 my father. His appointment as professor of astronomy 

 conferred benefit, not only upon the University of 

 Glasgow, but also upon the city and upon Edinburgh, 

 and the far wider regions of the world, where his 

 lectures were given and his books read. T^e benefit 

 we had from coming under his inspiring influence, 

 that creative influence, that creative Imagination, that 

 power which makes structures of splendour and beauty 

 out of the material of bare dry knowledge, cannot be 

 overestimated. 



FLOW OF STEAM FROM NOZZLES. 



IT is well known that when a gas is flowing from a 

 vessel by an orifice, If the outside pressure Is less 

 than sp,„ p^'he'ing the pressure In the vessel where the 

 gas is at rest, the pressure in the throat of the orifice 

 is never less than sp^, if s is 



where 7 is the ratio of the specific heats, s is 0527 

 for air. It is also known that, with fair accuracy, we 



