A 
t, 
4 
Be 
: 
: 
F 
u PRE eS ene 
MICROSCOPY. 247 
of Mr. Wm. Webb’s unparalleled success in micro-writing on glass. 
The specimens thus produced are regarded by Mr. Webb as decid- 
edly the best test-objects; and they may be obtained from Mr. 
Edmund Wheeler of London. 
- Webb says: —‘‘I engrave a series of Bee with letters 
measuring from one two hundred thousandth of inc 
two hundred millionth of an inch. Each engraving is of the 
Lord’s Prayer, varying only i in size, pe aguante about the thou- 
sandth of. an inch, which is at the rate of over a quarter of a mil- 
lion letters to the inch, and progressively decreasing the size, the 
next of the ser ies being at the rate of a million letters to the i ine ch, 
e ne 
and New Testament together consist of three million five hundred 
and sixty-six thousand four hundred and e ighty letters (for the 
convenience of a standpoint), I say the lastly enumerated test is 
at the rate of one Bible to the inch and en engrave the next at 
the rate of another Bible to the inch, and on decreasing at the 
rate of a Bible to the inch down to fifteen Bibles, or, at the rate of 
fifty-three million four hundred and ninety-seven thousand two 
hundred letters to the inc ch; but when it is ae ee that the 
letters are written within two perai lines, with spaces above and 
below for long letters, and to enable one line to þe distinguishable 
e Te and “u,” although averaged, with all other letters, with 
the sie and including spaces, “at the e fifty-three million four 
hundr ed and ninety-seven thousand two hundredth of an inch, 
tra space occupied by capitals, the spaces pee vere and the 
Space between one line of writing and the next line, it may be 
taken that the ‘‘e” actually occupies only EPSEN of fo aver- 
age, or, the two hundred and thirteen million nine hundred and 
mae a thousand eight hundredth of an inch. 
asurement does not stop at this arp as there are other 
steps to bë arid versed — as to one, the dot to an “i,” I say nothing 
now. As the “e,” it is self-evident ihat it is not a spot of 
black of the. previously estimated less than mo hundred millionth 
of an inch, but composed of a bent and twisted line across, an 
about the two hundred millionth of an inch; r horele the thick- 
ness of the line has to be considered, and, taking that at a lineal 
fifth of the space, the two hundred and odd millionth would have © 
to be multiplied by twenty-five as the agnar of EN hy aon would 
ot s 
lionth is itself loaded in, and consists of abraded black atoms, 
„Stated in w the cutting edge of tho glass letter, which atoms can 
