9 
1864. | Microscopical Science. T3E 
to yield important information. It is not, of course, to be supposed 
from these remarks, that we would try to limit its field of usefulness, 
for our object is, on the contrary, to endeavour to enlarge it. The 
advice we give has, in fact, this object in view, and is simply that if, 
instead of directly placing an object under the microscope, the observer 
will first take the trouble to examine it carefully with the naked eye, 
he will find himself in a far better position to form a correct judgment 
of its nature on seeing it under the magnifying-glass, than if he had 
omitted previously to do so. 
Having said this much regarding the observer, we must now turn 
our attention to his instrument. It is essential that it should be of 
good quality. When we speak of a microscope being of good quality, 
we do not mean that it should have handsome and elaborate brass work, 
for that part which is so attractive to the eye is the least valuable 
of the whole. °Tis in the object-glasses—’tis in the lenses, that the 
real value of the instrument resides, and thus it was that scientific 
men so long preferred the low-priced insignificant-looking foreign 
microscopes of Nachet and Oberhauser, to the elaborately got-up Eng- 
lish instruments. The foreign opticians sacrificed appearance to utility, 
while too many of our home manufacturers sacrificed utility to appear- 
ance. At the present moment, however, the British manufacturer is 
inferior to none, even in low-priced instruments, while, as is well 
known, his superiority in those costing from thirty guineas, and up- 
wards, has never been matter of dispute. 
Before speaking of the cheap instruments, we must first call special 
attention to the high-power object-glasses that have been recently con- 
structed by Messrs. Ross, Powell and Lealand, and Smith, Beck and 
Beck, the value of which it is scarcely possible to overrate, seeing that 
there can be no end to discovery, so long as there is no end to instru- 
mental perfection. In our opinion, the only boundary that human 
knowledge admits of, is that imposed upon it by the limited means 
of physical observation. Every additional magnifying power is, as it 
were, a new world gained. 
The progress of science, therefore depends as much upon the 
mechanician, as upon the observer, for the acumen of the latter would 
fail to reach its goal, if unassisted by the skill of the former. 
It will be recollected that Ross was the first to succeed in manu- 
facturing an object-glass of +: of an inch focus, and that shortly after- 
wards Powell and Lealand overstepped him by producing a +, which, 
for the time being, was regarded as quite a scientific curiosity. The latter 
manufacturers have now, however, stimulated by Professor Beale, out- 
stripped themselves, and actually manufactured a workable lens of no 
less than 3's of an inch focus. Since ‘then, Ross has improved his 34, 
and Smith, Beck, and Beck have produced az. Perhaps it will be 
better, if before describing the 25, we first say a few words regarding 
the +; of Ross, and the +5 as now supplied by Smith, Beck, and Beck. 
The advantages of the new 7: are its having a large front distance 
with a maximum of real angle of aperture. It will work through 
glass the +35 of an inch thick, and bear the highest eyepieces. These 
K 2 
