HDA/VC/46D
AIRMAIL
20th Octob*rp 1959
L. C. Laporte, Esq.#
P.O. Box 65006
MONTREAL 30,
Canada.
Dear L",,
Thank you for the copy of the report on K-3891, and of
letter of October 15th to Sir Charles. I had heard from
Sir Charles previously that your results showed the diminution
In tar and nicotine to be due to the increased filtration efficiency
which the addition of K-389 made to the cigarette rod, and I was
very interested to note that you found the retention coefficient
to be the same.
To put it in a slightly different way, this additive has
increased the pressure drop of the cigarette without affecting Its
burn qualities and the effect is the same as we should expect If,
by some method d' packing the tobacco red, we could, for the some
weight, have Inerqased the pressure drop by the same amount. it
therefore seems likely that the filtration of K-389 Itself to much
the same as that of tobacco. Would it be possible to make a
filter plug of this material and measure Its retention coefficient,
which should be about 47 If Ws Is so, it would prove the point
and we should have a little more data to add tQC our knowledge of
filtration.
By the -ways retention coefficients are markedly dependent
upon velocity and are much higher for a slow velocity togs 15 ml.
puff in 2 secondsp than for 35 ml. In 2 seconds. This is something
that we are Investigating at the moment but, roughly, for 35 ml. in
2 seconds we find retention coefficients ranging from 1.9 with coarse
Estron to 2.3 with fine Estron through viscose fibres 2.4 to 3.3,
paper and natural fibre (supertex type) 3.0 to 3.5, tobacco around jL - (,
46 paper filter (Schweitzer and Myria type) 5 to 6.
1 will be sending you shortly a device we have made for
rapidly putting together pressure drops, retentio'n coefficients and
filtration efficiencies which you may find intriguing and helpful.
With kindest regards#
C.C. C.S.F.Hobson, Esq. Yours sincerely,
@-r Charles Ellis
Ir.D.G Felton copy
I r. I .N. Hughe
CrI.
C=)
BATCo document for Province of British Columbia 21 April 1999