The sun. [volume] (New York [N.Y.]) 1833-1916, 1902-11-02

book and the plates and the manuscript
were to be destroyed. could produce the
book again by calling my memory into ser
vice. Once these problems get into my
head they seem to stay there in all their
minute details
In such manner produced the copy
FOR both my books. As the point system
Of writing is based on punctures in paper
made by "A stylus. similar to holes made
by pin point in paper, you can read
lily see how long | was about the task. cs-
pecally when you bear in mind that l had
TO create in this writing all the manv difier-
ent Characters used in the Variations.
of course. after | lad written down the
problems some one had 10 transcribe them
In ordinary writing. My brother Addison
wrote the first book for me; my wife has
just finished this task with the second.
When the proofs Of my first book came.
Addison read them to ME and made the cor
rections that ] ordered Only a half dozen
mistakes have been found in the book in all
these years. and these are misspelled words
in addition to my memory l have had
recourse to the slate for he blind.
This slate is a square board cut mp into
little s!nken squares into which are placed
type-ike affairs that represent certain
figures. For instance, the numerals are
made almost wholly by the use of the Letters
I and V.
In its proper position, T represents
the numeral one. Turned on its side and
with the cross line TO the left it is two.
With the cross lire down il is three. and with
the cross line to the right it Ia four.
" in It's natural position is Ave; with tho
opening To the left /, is six: with the open
ing down, seven, and with the opening TO
the right, eight. l. represents nine, and a
blank type naught.
There also are characters for simple
algebra, but none higher. Therefore, !
have had TO develop a system Of my own,
using tie regular and few types employed
10y the blind. for could get no one To cast
the various queer characters that l
needed.
This system is often complex, owing to
the fact that | have had to employ all the
myriad characters known TO algebra, geom-
etry, Tigonometry and calculus, which last
branch includes Greek alphabetical char
aCters
Here again in my work memory plays
large part for it would never do to for
get the scores of names | have given the
ordinary types "a he uses to which have
pu, them.
This Is an example Of how ] use my
slate. | take a common algebraic char
acter, and 10y turning it, as / and are
turned to secure the numerals. | obtain the
eight trigonometrical functions. sine. co.
sine, versed sine, coversed sine. tangent
~, tn ant IND
1T Is only on rare occasions. however
that | use the slate. | much prefer 10
solve problems while pacing my room
and have to sit down when | work with
the slate"
Here Mr.. CARL raised warning hand.
But don't envy me my memory he
said laughingly. y fear that for many
ordinary uses, it isn't much good.
~Why. do YOU know that it's fact tina,
can not do simple problems in addition
subtraction. mutt plication and division
in my head' When | want to figure up
my living expenses. for instance. | am
compelled to seek aid OF my slate. Strange
isn't it;
Neither am | lpltning calculator
M YOU might be led TO think from my math-
ematiral reputation. | work with pains
taking slowness from sheer inability 10
grasp things mathematical quickly.
Il do believe that my brain when it
Ia wrestling with figures, moves as slowly
a. that Of a boy just beginning 20 learn
the significance of the multiplication
tables
Mr.. CARL is going to call his new book
-Afterthoughts on Calculus OF Variations
- As .a1 ln ,
formidable problems known in pathe-
mates, which also have formidable sound
ing name-isoperimetrica problems.
Although Mr. CARL gained immediate
fame after his first book appeared, he is
known personally to very few mfthe-
matiCians. The absence Of sight has kept
him from attending the gatherings Of the
learned mca Of figures. but it has not pre-
vented him from instructing eminent
schC lar4 10y mail.
Prof. Simon Newcomb, the famous
astronomer. is representative Of the men
who have sat at Mr.. Carll's feet.
Mr. CARL is fellow Of Columbia Uni
versi,y MAYOR Low secured Mr.. Carlll
the fellowship in recognition Of his work
Every year he delivers a course of lectures
at the university 10 the mathematical pro-
fessor-, among whom are DR.. Thomas Fisk
and Prof. j. H. Van Amringc, head of the
mathematical department. The late Prof.
William G.. Peck of Columbia o ftsn con-
suited Mr.. CARL.
Mr.. CARL is slight in stature and build
and remarkably free Of the nervousness
usually bited by close students. When
he stated that he was in his sixtieth year,
he added rather pathetcally.
Locking back over these years my one
regre, is not so much that | am blind as
that I've forgotten nearly all ever knew Of
my Lat in and Greek.