46 



NA TURE 



[March i i, 1909 



the House was only saved from being counted out on 

 two occasions b}' sufficient members rushing in to 

 form a quorum. The substance of the Bill was given 

 in last week's Nature. Briefly, it is proposed that 

 at 2 a.m. on the third Sunday in .-Xpril of each year, 

 all clocks shall be put forward one hour, and shall 

 remain in advance of Greenwich mean time and 

 Dublin mean time by this amount until 2 a.m. on the 

 third Sunday in September, when the hands are 

 to be put back again. 



\\'e do not propose to repeat now the substantial 

 arguments against this proposal stated in these 

 columns on July 9, 1908, but we do suggest that the 

 article could be read with profit by the members who 

 voted for the second reading of the Bill, which was 

 for the second time referred to a Select Committee 

 ■of the House of Commons. During the debate many 

 illustrations were used to convey to the minds of the 

 members some idea of the relation between local time 

 and mean time, and of daylight to business hours. 

 No one pointed out, however, that it would be more 

 reasonable to change the readings of a thermometer 

 at a particular season than to alter the time shown 

 t)V the clock, which is another scientific instrument. 

 Perhaps it is contemplated to bring in a Bill to in- 

 crease the readings of thermometers by ten degrees 

 during the winter months, so that 32° F. shall be 

 42° F. One temperature can be called another just 

 as easily as 2 a.m. can be expressed as 3 a.m. ; but 

 the change of name in neither case causes a change 

 ■of condition. 



The argument that inconvenience is not felt by 

 travellers on the Continent changing their watches t'- 

 mid-European and east-European time, or by the 

 five standard times of America, has little bearing 

 upon the question. The inhabitants of any of these 

 regions use a particular standard time, as we use 

 Greenwich time, but their hours of work and leisure 

 are determined by national custom. The most note- 

 worthy characteristic of life in France and Germany 

 is the earlier hours at which places of business open 

 In the summer compared with those usual in our 

 cities. In Germany many schools open at 7 a.m., 

 and the usual hour is 8 a.m. The people adapt them- 

 selves, therefore, to the daylight hours instead of 

 pretending to do so by putting on the clocks by one 

 hour in April and back an hour in September. In 

 all places between the same latitudes as those of the 

 British Isles, the relation of daylight to the time of 

 the standard meridian is the same, so that whatever 

 arguments can be advanced in favour of the proposed 

 seasonal change of time in our country, beyond those 

 of custom, would apply equally to the inhabited zone 

 between fifty and sixty degrees completely round the 

 world. 



It is only in a few great cities in England that 

 the waste of daylight described by the supporters of 

 the Bill really exists; and even in these places it is 

 pii^sible for people to rise an hour earlier for work 

 -or recreation if they desire to do so. Industries and 

 occupations which can best be carried on in daylight 

 make the fullest use of daylight hours at present, 

 without any legislative compulsion, .'\gricultural 

 operations begin shortly after sunrise during a large 

 part of the vear, and continue until nearly sunset; 

 in the building trades the hours of work vary with 

 the hours of daylight, and the same is true in most 

 engineering shops. But when work or pleasure can 

 be carried on equally well in artificial light, there is 

 a tendency to continue it to the limits of endurance. 

 So it has come about that the bedtime hour in cities 

 has been pushed further and further into the night, 

 and the hour of rising has become later. 



All that is needed is for banks, places of business, 



NO. 2054, VOL. 80] 



and schools to open at an earlier hour during the 

 summer months, as they do in most places on the 

 Continent. To introduce confusion into the whole 

 svstem of time-reckoning because some people in 

 cities have not sufficient strength of mind to make 

 the best use of the daylight hours would be to 

 acknowledge that, as we cannot alter our national 

 habits and customs, Acts are passed by which we 

 pretend to change them while they remain the same. 



?ROF. JULIUS THOMSEN. 



THE two great enrichers of thermal chemistry 

 were Berthelot and Thomsen. Berthelot died in 

 the spring of 1907, at the age of eighty ; Thomsen 

 has just left us, at the age of eighty-three. Born at 

 Copenhagen in February, 1826, and educated in the 

 polytechnic there, Thomsen became professor of 

 chemistry in the university of his native city in 1866 ; 

 he retired from the duties of his post in 1901, but 

 continued to liv-e and work in Copenhagen. 



Julius Thomsen devoted his life to the experimental 

 advancement of thermal chemistry. His first memoir 

 on this subject was published in 1853, his last a few 

 years before his death. 



The permanent memorial of Thomsen 's work is 

 the four volumes of " Thermochemische Unter- 

 suchungen," published in the years 1882-86. In the 

 vear 1780 Lavoisier and Laplace announced that " all 

 thermal changes . . . exhibited by a system of 

 bodies which changes its state repeat themselves in 

 the opposite direction when the system returns to its 

 original condition." This generalisation was deduced 

 from a theory of heat, and was to some extent 

 verified by experiments. In the years 1839-42 Hess 

 laid the foundations of thermal chemistry, sketched 

 the lines on which the structure should be built, and 

 began the building. Thomsen began his work soon 

 after the appearance of Hess's memoirs. He has 

 formed a stately building — adorned perhaps with too 

 manv crockets and pinnacles — resting on the sure 

 foundation of experimentally established facts. 



In the preface to his great work, " Thermo- 

 chemische Untersuchungen," Thomsen tells us that 

 he formed the plan of the whole before he began his 

 experiments, and that he adhered almost rigorously 

 to that plan. When the work was nearly completed, 

 he recognised that the science of thermal chemistry 

 would be benefited by collecting and digesting his 

 materials, and so he published his investigations and 

 his theoretical discussions thereof in the four volumes 

 which have established his fame. In 1905 Thomsen 

 published a resum^ of his principal experimental 

 results and discussions in one volume. Unfortunately, 

 that book was written in Danish ; fortunately for 

 English workers in the field of thermal chemistry, 

 an English translation of it has appeared in Long- 

 mans' series of text-books of physical chemistry, 

 edited by Sir William Ramsay. 



Thomsen set out with a determination to extend 

 his thermal investigations over the whole field of 

 chemistry. He carried that determination into effect. 

 The first volume of the " Untersuchungen " deals with 

 the thermochemical aspects of the neutralisation of 

 acids and bases. The second volume is devoted_ to 

 the reactions, and the classification of the affinity- 

 phenomena of the non-metallic elements. The third 

 volume is concerned with measurements of the heats 

 of dissolution in water, with hydration, and with the 

 affinity-phenomena of the metals. The thermo- 

 chemical investigation of carbon compounds is the 

 subject of the fourth volume. 



The most important results of Thomsen's examina- 

 tion of neutralisation were the firm establishment of 



