XXXVI 



mathematical conceptions of chemistry, which he himself called 

 "Newtonian chemistry," greatly engrossed his attention. He endea- 

 voured to develop the consequences of a theory of chemical combina- 

 tion depending on the assumptions that in chemical actions energy 

 was conserved as well as a quantity analogous to areas. Our know- 

 ledge of the dynamics of molecules is hardly great enough to 

 criticise such a theory effectively. 



Dr. Haugh ton's work in the field of geology includes contributions 

 upon subjects of a very diverse nature. He has written extensively 

 on mineralogy, petrography, physical geography, and physical 

 geology. 



Mineralogy first claimed his attention, and in 1853 he began to 

 publish a series of papers on Irish minerals. One of the last of 

 these dealt exhaustively with the fine meteorite which fell at 

 Dundrum in co. Tipperary, and which through his instrumentality 

 was presented by Lord Hawarden to the Museum of Trinity College. 



His petrographicai communications are still more numerous and 

 important. His work on the Irish granites is singularly complete, 

 and was commenced in 1856, at a time when the use of the petro- 

 graphicai microscope had riot been revived by Sorby. When this is 

 taken into account we cannot help being struck by the results 

 obtained by Haughton. 



A highly interesting observation is contained in his papers on the 

 Trap Dykes of the district of Mourne and on the Carlingford 

 Granite. He detects a chemical reaction between the intruding 

 granite and the limestone, and points out how the granite is thereby 

 altered to what may be called a Syenite. 



On the subject of physical geology Haughton contributed many 

 papers to the 'Proceedings of the Royal Society ' and elsewhere. 

 The first of the series relates to the effect on the distribution of 

 climate in geological time from the shifting of the earth's axis, due to 

 continental upheaval. Haughton arrived at the conclusion — which 

 is in agreement with the views of Professor G. Darwin — that the 

 effect would be insignificant. In a paper which appeared in 

 ' Nature,' Haughton estimated the whole duration of geological time 

 as 200 million years. This opinion he based on the probable rate of 

 formation of stratified rock. He assumed these to possess a thick- 

 ness of 177,200 feet. He likewise investigated the question of 

 geological climate in connexion with Rossetti's ' Law of Cooling,' 

 and arrived at the conclusion that the secular cooling of the sun 

 has been the chief factor in changes of geological climate. 



In 1858 he published in the ' Philosophical Transactions ' his 

 important work on the joint-planes of the Old Red Sandstone of 

 co. Waterford, and with this also may be associated his observations 

 on the remarkable uniformity in magnetic bearing of the joint-planes 



