72 PETER GUTHRIE TAIT 



during the summer months of 1868 undertook, the next winter session, the 

 systematic teaching of students in practical physics. 



In this small upper room stripped of its benches, but with the terraced floor 

 left intact, the men were put through a short course of physical measurements, 

 such as specific gravities, specific heats, electrical resistance, and the like. Any 

 who showed talent were soon utilised by Tait in carrying out original research ; 

 and, to facilitate this kind of work, every possible corner of the old suite of 

 rooms of the Natural Philosophy Department was adapted by means of slate 

 slabs built into the thick steady walls for the installation of galvanometers and 

 electrometers. The small room which Professor Forbes had used as his 

 sanctum became the centre of experimental work. In this room Forbes had 

 made his classical researches in polarisation of heat ; and here also Tait, 

 with the help of successive sets of students, made his novel discoveries in 

 thermoelectricity. 



The large class room was also used as a research room, especially during 

 the summer session when (at least until well on in the seventies) no class met. 

 Two slate slabs were built into the wall, one on each side of the blackboard ; 

 and on these were placed the mirror galvanometers and electrometers necessary 

 for delicate electrical investigations. 



Robertson Smith remained with Tait till 1870, and found time to carry 

 through an interesting piece of experimental work on the flow of electricity 

 in conducting sheets. In the paper giving an account of these experiments 

 he considerably simplified the mathematical treatment, which had already 

 engaged the attention of Maxwell and Kirchhoff. Among the students who 

 passed through the Laboratory during the first and second years of its existence 

 were Sir John Murray, Sir John Jackson, and Robert Louis Stevenson. 

 Stevenson was paired off to work with D. H. Marshall, who succeeded Smith 

 as assistant in 1870 and is now Emeritus Professor of Physics of Queen's 

 University, Kingston, Ontario. Marshall of course was keen in all things 

 physical, while Stevenson's preference was for a lively interchange of thought 

 on every thing of human interest except science. When, as frequently 

 happened, Stevenson got weary of reading thermometers or watching the 

 galvanometer light-spot, he easily found some excuse to bring Robertson 

 Smith within hearing and set him and John Murray arguing on the age of 

 the earth and the foundations of Christianity. In some idle moments these 

 lively students broke Tait's walking-stick. In haste and trepidation they 

 commissioned two of their number to buy another as like the shattered one as 



