DAMAGE DONE TO TREES BY THE SHALE INDUSTRY. 471 



coloured mark becomes visible. Everything, even the flowers of 

 recent growth, are dirty and blacken the hands of anyone who 

 picks them. 



The result of this is that trees have died. First in order came 

 spruces and silvers of all ages, and other full-grown conifers of all 

 sorts. Then oaks and beeches, and any full-grown trees which 

 were much exposed. But, except in the case of great exposure, 

 sycamores and limes do not appear to suffer to any great extent, 

 while elms have survived, though they have become unhealthy 

 and stunted in exposed situations. Some oaks, which were very 

 much exposed to the refinery which manufactures sulphuric acid, 

 died with extraordinary rapidity. Within five years of their 

 being green trees, they were not only leafless, but became gaunt 

 poles without even a vestige of bark upon them, and the small 

 twigs had all disappeared. Young trees do not die so quickly, but 

 oaks and beeches do cot thrive, and it does not seem worth while 

 to plant any species of conifers, though they may live for a few 

 years ; Austrians and larches probably survive longer than any 

 other species. As one would expect from observation of the older 

 trees, the young trees which thrive best are sycamores and limes. 

 Black Italian poplars grow fast and seem to thrive, but they have 

 not yet been observed to attain maturity. The trees in the 

 neighboui'hood of other shale-works do not show such results, nor 

 are they affected so quickly; but few, if any, other works are so 

 large as the one referred to, and it is unknown to the writer 

 which, if any of them, manufactures the sulphuric acid used in 

 their refineries. 



It would appear, therefore, that the shale-works are of them- 

 selves deleterious, and that they become very much more so when 

 the sulphuric acid is manufactured on the spot. So much for the 

 general results. 



With regard to particular observations of different trees, a few 

 examples may be of interest. Full-grown oaks first show that 

 they are affected by becoming stag-headed, and then they die 

 downwards with varying rapidity. In those which died quickly 

 and lost their bark, the sap-wood was quite gone, but the red 

 heart-wood did not appear to be affected. Beeches become 

 gradually thinner, and frequently show a sort of eruption of the 

 bark. Sometimes the eruption occurs without the foliage of the 

 tree showing serious diminution, at least for a time. In one 

 instance the writer observed the lower leaves of a beech, which of 



