EXPERIMENTS WITH PAPER FILTERS. 
437 
and would cause him to turn his attention to other and more profitable productions ; 
this would naturally have the effect of diminishing considerably the ensuing crop and 
raising its price. It is only in the furthest districts from Smyrna that the grower is 
obliged, as it were, to cling to opium ; for the expense of transit prevents the exporta¬ 
tion of all other articles, which, remaining for local consumption, command only a low 
price. But as opium alone, on account of its small bulk in comparison to value, can 
bear the forwarding charges, it is almost, under any circumstances, the best paying 
article for the said districts. 
• The fact must not be overlooked, that the demand is still slowly but steadily increas¬ 
ing, and that, on the other hand, the productive capacities of the opium districts are at 
their climax. When, therefore, prices are under or about a corresponding crop out of 
the last ten years, the opportunity should not be missed. 
With reference to the average price of some twelve to fifteen years ago, it must be 
observed that the necessaries of life were at that time so much cheaper, that the then 
11s. 6d. was perhaps more remunerative than the 16s. 6c/. of the last ten years. 
[Note. —This paper was published in Smyrna (Asia Minor), in April, 1868, in pam¬ 
phlet form, by the author, who, in prefatory notes, states that it was given at the re¬ 
quest of several friends, and is based on his personal knowledge .]—American Journal of 
Pharmacy. 
EXPERIMENTS WITH PAPER FILTERS. 
The filter most commonly employed in analytical laboratories is a circular piece of 
paper folded twice upon itself into the form of a quadrant, and supported on a glass 
funnel with straight sides. This filter, though commendable in so far as it is capable 
of supporting the weight of a considerable column of liquid without breaking, is objec¬ 
tionable, inasmuch as liquids cannot pass through it so rapidly as is desirable. Since at 
almost every point the paper is in close contact with the glass, but little of the liquid 
can flow off between the filter and the sides of the funnel. 
Several schemes have at various times been proposed for opening waterways between 
the glass and the paper; the interposition of straws, glass-rods, and splinters of wood 
between filter and funnel, as well as fluted funnels and plaited filters—are all devices 
looking to this end. 
The advantages of the plaited filter are so great that some chemists prefer to use it, 
even in quantitative analysis, instead of the common form, in spite of its greater liability 
to break, and the difficulty of washing the precipitate. 
In the laboratories of Professors Lawrence, Smith, and Ordway, among the most 
accurate of American analysts, plaited filters are said to be employed to the almost total 
exclusion of the plain form. 
Another excellent method of increasing the speed of filtration, first suggested in this 
country by the German chemist, Fleitmann, consists in placing one plain filter within 
another of coarser fibre; for instance, a fine plain filter of Swedish paper may be placed 
within another plain filter of coarse German paper, supported, as usual, on a funnel. 
In experimenting upon these various forms of filters, it occurred to me to fold the 
plain qualitative filter in two operations instead of one. In place of folding the filter 
doubled upon itself down the middle in the usual way, I proposed to turn down on each 
side of the paper a fold equal to one-quarter of the semicircle, and then to fold the 
sectors of 45° arc thus formed back upon themselves. 
The filter is then opened without disturbing the folded portions, and placed upon the 
funnel. In this form the triple side of the plain filter is broken up, and the folded por¬ 
tions keep open passages, instead of hinderiug filtration. 
This filter, as tried against the plain form, gave, 1st, 133 : 100. 2nd, 111 + : 100. 
3rd, 205 + : 100. 
Two plain filters ran equally in several trials; each was changed into the other’s 
funnel, and No. 1 ran 33 per cent, less than No. 2. No. 1 was dried and folded into my 
form; remaining in the same funnel, it ran 32 per cent, faster than the other. Both 
filters were then opened, and showed no tear or weakness when held against the light. 
As these filters gave different results in different funnels, I thought I would ascertain 
the cause. The water seemed to be retarded in its passage by the attraction of the 
