Mr. Lax on a Method, &c. 
233 
parts and laid upon the instrument, I will not trouble you with 
the deduction which I have made. It is understood indeed, 
that Bird's method is now generally laid aside, and that each 
artist employs one, which he considers in many respects as 
peculiar to himself; but I presumed that there would still be 
such a connection betwixt Bird's method and those which have 
been substituted in its stead, as to render them in some degree 
liable to the same errors to which it was subject, and the re- 
ports which I have uniformly received from persons, who have 
had an opportunity of examining some of the modern instru- 
ments, have fully convinced me that my opinion was just. 
But whatever may be the nature of the methods wdiich are 
now in use, or whatever their advantages over Bird’s, I never 
could persuade myself that it w r ould be safe to trust to an in- 
strument, without a previous examination. To discover the 
means of accomplishing this object, is what I have for some 
time been anxious to effect, and though I fear my endeavours 
have not been very successful, I will nevertheless take the 
liberty of presenting you with the result. 
You are aware, I believe, that I use a circular instrument 
for observing both in altitude and azimuth, which was made 
for me by Mr. Cary in the Strand ; that the radius of both 
the altitude and the azimuth circle is one foot, and that each 
is divided into parts containing ten minutes. The construction 
of this instrument does not differ materially from that of other 
similar instruments, with which you are well acquainted, and 
I shall not therefore waste your time by giving you a parti- 
cular description of it. For the purpose of examining the 
divisions upon the two circles, I procured an apparatus to be 
prepared by Mr. Cary, which wall be very easily explained. 
