18S5.] NEW YORK ACADEMY OF SCIENCES. 63 



buildin.ir stones. But even it is not proof against the disinte- 

 grating forces. The Obelisk is unfortunately an illustration. 



I saw the Obelisk for the first time about six months after its 

 erection in Central Park. Being interested in the preservation 

 of stone, I examined it as carefully as I could from a distance, 

 and saw how rough the western and southern sides were, but, 

 being unable to approach it closely, could form little idea of the 

 actual condition of the surface. 



On many subsequent occasions, I examined it closely, and 

 after a time found small pieces of the granite lying around the 

 base, which, to me, clearly proved that it was being affected 

 by the severe climatic influences. 



Piofessor Doremus accompanied me, about a year ago last 

 September, to examine the obelisk. We gathered quite a quan- 

 tity of it from around its base. He showed the pieces we had 

 picked up to the late Commander Grorringe, who could 

 hai-dly believe they came from the monolith, and expressed the 

 hope "that some day it would be polished. Hence Dr. Doremus 

 refrained from pressing the matter of its preservation with the 

 park commission. 



On his return this summer from Europe, the then President of 

 the Board, Mr. J. D. Crimmins, wrote to Professor Doremus re- 

 questing his opinion and advice, which resulted in his letter pub- 

 lished last Septembei'. 



The Hon. M. E. D. Borden was finally intrusted with the de- 

 cision as to the proper treatment ta be adopted. After consul- 

 tation with Prof. Doremus, and a visit to the obelisk with him, 

 Mr. Borden decided on the paraffine compound application. On 

 September 22d, ult., we received a letter from tiie Park Com- 

 missioners requesting us to treat the north side of the plinth as 

 a specimen of our waterproofing process. 



On September 25th, my son and I went to the obelisk, and 

 commenced the work, wlien I discovered that I could remove 

 quite large scales with my finger-nails from the surface of the 

 plintli, and also that there was a green vegetable growth behind 

 each piece removed. 



This was so serious that I thought it better to call the atten- 

 tion of the authorities to its condition before proceeding with 

 the work. 



It took my son and myself several hours to take off the decayed 

 portions. We then applied the water[)roofing compound. I 

 watched very closely the effect of the heat upon the stone, as so 

 much had been said against using it, and found that it stood the 

 necessary temperature perfectly well, not being damaged in the 

 slightest degree. 



