31$ MEASURE OF A DEGREE ON THE COROMANOEt COAST. 



I had made a great many experiments prior to .the mea* 

 Suretnent, but found great irregularity, partly from not at- 

 tending sufficiently to the above circumstance, and partly 

 from the unsteadiness of the drawing post, notwithstanding 

 it was driven deep into very hard ground, and secured, as I 

 thought, by having large stones pressed close on each side 

 of it. To remedy this latter inconvenience, I had a staple 

 driven into a brick wall, into which the iron was fixed with 

 the adjusting screw for the chain, after which I perceived a 

 perfect coincidence with the arrow and mark on the brass 

 head, except what arose from the trifling expansion and con- 

 traction of the iron which held the chain. I then began a 

 Bew course of experiments on both the chains, and the re- 

 sults were as follows. 



Experiments for determining the expansion of the new 

 Chain. 



Expansion of 

 the standard 

 chain. 



Mean -00752 



Experiments 



