so ASTRONOMICAL OBSERVATIONS. 



confidcrable part of the plan was executed. 1 firfl: endea- 

 voured to lay off the parallels with a chain ; but from its great 

 uncertainty, owing to itj expanfion and contraftion with heat 

 and cold, and the bending and ftraightening of the links, 

 was under the neceflity after making many trials of laying it 

 wholly afide, and in its place made ufe of wooden meafuring 

 rods, formed like a carpenter's fquare : thefe rods were truly 

 graduated, and accommodated with plummets and Aiders, by 

 the due management of which, the mcafurements were always 



horizontal. After adopting the ufe of the rods I had but one 



difficulty for fom_e time to contend with, which was the tallies 

 being fometimes returned erroneous for want of the neceffary 

 care in the meafurers. The next difficulty was of a much more 

 ferious nature ; it was the points of interfeftion of fome of the 

 leading avenues which fixed the pofition of other ftreets being 

 moved. Upon making this difcovery I at firft fufpefted that 

 it had been done by fome perfon, or perfons through inadvef- 

 tence ; but from fubfequent events am inclined to think it was 

 the effeft of defign. I have mentioned this circumftance to 

 lliew the neceffity of a conftant attention in thofe intruded with 

 the execution of fuch complicated plans to the pofition, and 

 fitnation of all the leading points. 



After the principal avenues were fixed, great part of the work 

 could be examined and correfted with mathematical exaftnefs, 

 dnd the fmalieft efror in any cif the meafurements detefted^wifih 

 certainty. 



The following are the the inclinations of fevefal of the lead- 

 ing avenues to the meridian. 



Maffachufetts avenue eafl of t(l fireet weft, and North 1 

 Carolina and Georgia avenues, make an angle with the }> 62° 29' 32" 

 meridian of - - - J 



Virginia avenue eaft ward from the place where the Equef- "j 

 trian Statue of General Wafliington is to be placed, makes an ^ 70 18 5 

 angle with the meridian of - - J 



Pennfylvania and Maryland avenues, eaft of the caprtol,7 , 

 make an angle with the meridian of - - j ' 



Kentucky and an avenue net yet named, mftke an angle 7 



•.1 .1 • J- r " f 'ZZ CO 00 



With the meridian ot : - - y jj 



Water ftreet between 7th and 12th ftreets weft, makes an 7 1 ro 



angle with the meridian of . - - j 44 49 5 



New Jerfey and Delaware avenues, make an angle with? ^^ 



the meridian of - . . - j 5 43 -t 



Pennfvlvania 



