Year: 1888

page_text: Date of Application, 12th Jan., 1888
Complete Specification Left, 27th Oct., 1888
Complete Specification Accepted, 30th Nov., 1888
1 JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been com-
municated to me from abroad by Henry J. Doerr of Newark, Essex County, New
Jersey and Theodore Mace of 182 Fulton Street New York both in the United
States of America to be as follows:-
This Invention relates to improvements in mercurial air pumps of the Sprengel'
type wherein air is exhausted by the descent of mercury in a vertical tube and has
for its object to effect a continuous and steady flow of the mercury whereby one
mercury elevating apparatus will suffice for the operation of several sets of mercury
tubes and whereby the part of the device can be easily separated for cleansing or
other purpose.
In a pump made according to this Invention the main mercury reservoir has a
downward extension and from the reservoir rises a tube on the upper end of which
is a bulb. In the opening in the top of the reservoir and in the tube just below
the said reservoir are air tight plugs. Passing through one of these plugs is a
tube closed at its upper extremity but near the said extremity it has a delivery
orifice. This tube extends nearly to the bottom of the downward extension of the
reservoir and is open.
From the lower portion of the bulb a pipe leads to a vessel forming an air seal
in the upper part of which is a stopper through which passes a tube the open lower
end of which is near the bottom of the said vessel, which thus forms an air trap to
prevent any air in the mercury from being carried into the fall tubes. The tube
which passes through the stopper as aforesaid leads into a chamber in which it is
hermetically sealed and in the side of said tube are several openings. Extending
between the lower portion of the aforesaid chamber and the upper portion of a
second similar chamber is a series of fall tubes. This second chamber communi-
cates by a pipe with the upper portion of a second bulb. At the lower part of this
bulb is a passage communicating with a valve chamber in which is
provided with projections on its lower side, so that said valve can close the
D
a valve

page_text: opening between the said passage and chamber but not the opening from the said
chamber to a pipe which communicates with the extension of the main mercury
reservoir.
Opening into the upper part of the said valve chamber is a short pipe com-
municating with a second valve chamber in which is a valve provided with
projections on its upper side so that this valve can close the opening from the
second valve chamber to the said short pipe but not from the said chamber to a pipe
which by a connecting tube communicates with the tube connecting the main
mercury reservoir with the bulb above it.
From the upper part of the chamber from which the fall tubes extend an exhaust
tube communicates with a chamber in which phosphoric anhydride or any other
suitable material may be placed for drying the air exhausted. This drying chamber
communicates by pipes with a pipe to which are connected the pipes and fittings to
which the bulbs or other vessels to be exhausted are secured.
The chamber to which the fall tubes extend is provided with stoppers through which
pass the ends of the said fall tubes so that by removing the said fall tubes from
these stoppers and the tube from the stopper in the aforesaid vessel beneath the
chamber to which the fall tubes extend the apparatus can be taken apart.
The operation of the apparatus is as follows. A vacuum pump of any ordinary
or suitable construction is applied to a tube which enters the bulb above the main
mercury reservoir through the upper stopper and a pump producing alternately
vacuum and plenum is applied to the end of the tube from the second valve
chamber.
Suppose that the last mentioned pump first forces air into the last named tube the
valve in the second valve chamber will be forced down upon its seat and hermetically
closed. The air will pass into the tube above the main mercury reservoir and by
pressing on the mercury will force it into the bulb above. This upward flow of
mercury will be assisted by the vacuum caused in the said bulb by the first named
pump which constantly draws out air. Meanwhile the pressure on the mercury
column in the main mercury reservoir, the downward extension, the pipe therefrom
to the valve chamber and the said valve chamber forces the valve in the latter tightly
to its seat.
From the bulb the mercury passes by the pipe through the vessel forming an air
seal to the tube therein and then it falls through the fall tubes. In this way as is
well known air may be entrained by the descending mercury and drawn out of the
bulbs or vessels being exhausted. The mercury and entrained air then pass into the
second chamber and to the second bulb beneath it.
On the exhaust stroke of the pump connected with the second valve chamber the air
in the said bulb is drawn out through the tube connected therewith the valve therein
lifting. At the same time however air is exhausted from the tube above the mercury
in the main mercury reservoir. There is also the constant vacuum maintained in the
tube passing through the said reservoir as aforesaid. The vacuum produced in the
second bulb obviously draws the mercury through the system and into the said
bulb. Now the mercury which has traversed the system has been taken from the
main mercury reservoir and hence the mercury level in said reservoir will have
fallen. The moment therefore that the vacuum is produced above the mercury in
the said reservoir then the weight of the mercury which has entered the second
bulb is free to push down the valve in the first valve chamber opening the valve
therein and the mercury in the bulb flows into the said valve chamber and so
back by the pipe therefrom to the main mercury reservoir.
When the apparatus is arranged with several sets of fall tubes the tubes between
the first bulb and the vessel constituting the air seal and between the second
chamber into which the fall tubes open and the second bulb beneath are extended.
- With the first named tube several vessels constituting air seals communicate by
.branch tubes and with the last named tube several chambers into which the fall
tubes open communicate by branch pipes. The mercury from the bulb above the
main mercury vessel passes along the first named tube and is distributed to the

page_text: several sets of fall tubes through the air seals and corresponding chambers above
them. Then from the chambers into which the fall tubes open the mercury passes to
the second bulb as already explained.
By this construction several sets of bulbs or vessels can be exhausted simulta-
neously by the aid of a single mercury elevating device thus greatly augmenting the
economy of construction as well as the capacity of the apparatus.
According to a modified construction air pressure is employed at or below normal
to elevate the mercury to the top of the fall tube and a vacuum is produced in a
reservoir into which the mercury passes after its descent through the said tube. The
last mentioned receiving reservoir is arranged above the reservoir from which the
mercury is originally drawn & a duct is provided leading downwardly from the
former to the latter. In this duct a valve is placed opening downwardly and so
arranged as to support the entire weight of the mercury column in the receiving
réservoir: This valve operates automatically to allow the mercury to escape from the
said receiving reservoir and into the main mercury reservoir whenever the weight of
the mercury above the valve exceeds the upward pressure of the mercury in the duct
bélow the valve. In this way a constant circulation of mercury through the system is
maintained by the agency of a single mechanical air pump which operates to exhaust
air from a suction tube leading from the mercury in the main reservoir, and also from
a branch tube leading to the receiving reservoir. The air pressure above the mercury.
in the main reservoir remains constant at atmospheric pressure or by closing the air
inlet, this pressure may be reduced owing to the expansion of the air in the then
closed tube so that a regulation may thus be secured to achieve the best working
results. The air pressure above the mercury is not increased by any additional device
nor is the same intermittently altered.
As in the former case the main mercury reservoir has a downward extension and
from the reservoir rises a tube on the upper end of which is a bulb in the opening in
the top of which and in the said tube just below the said bulb are air tight plugs.
Passing through one of these plugs is the tube as aforesaid. At its upper extremity
this tube is closed, but near said extremity it has a delivery orifice. The said tube
extends nearly to the bottom of the downward extension of the main reservoir and is
open as hereinbefore described under the first arrangement. There is a tube to which
may be connected any ordinary or suitable air pump. One branch of this tube passes
through the other of the aforesaid lugs into the bulb. The other branch cominuni-
cates with a second bulb by a tube. This second bulb communicates by a duct with
the extension of the main reservoir. In the duct is a valve chamber containing a
valve provided with projections on its lower side, so that while it may close the
upper opening in its chamber it cannot close the lower opening therein.
From the lower portion of the first named bulb a pipe leads to a vessel in the upper
part of which is a stopper through which passes a tube the open lower end of which is
near the bottom of the vessel. The vessel thus forms an air trap to prevent any air
in the mercury from being carried into the fall tubes. The tube passing through the
stopper leads into a chamber in which it is hermetically sealed. In the side of the
said tube within the said chamber is an opening.
Extending between the lower portion of the said chamber and the upper portion of
a second and similar chamber is a series of fall tubes. The second chamber com-
municates by a pipe with the upper portion of the aforesaid second bulb.
From the upper part of the said chamber a pipe leads to a chamber in which phos-
phoric anhydride or other drying agent is placed. This drying chamber communicates
by pipes with the bulbs or articles to be exhausted.
Finally communicating with the tube rising from the main reservoir is a pipe
which may open into the atmosphere and be provided with a stop cock.
The operation of this apparatus is as follows:-A quantity of mercury is placed
in the reservoir and is prevented from flowing into the bulb by the automatic closing
of the valve. The stop cock in the pipe opening to the atmosphere is now opened and
and a mechanical air pump is applied by which means air is exhausted from the first
and second bulbs. The production of a partial vacuum in the first bulb and the

page_text: pressure of air admitted above the mercury, causes the mercury to rise and escape into
the first bulb from which it flows through the air trap into the chamber above the fall
tubes whence it falls through the fall tubes and enters the chamber below whence it
passes to the second bulb from which it flows finally past the valve and through the
communicating pipe back to the main reservoir.
The mercury descending through the fall tubes entrains with it the air therein
and exhausts the air from the communications drying chamber and articles to be
exhausted. The exhaustion mechanically caused as aforesaid produces a partial
vacuum both in the first bulb and therefrom in the entire system back to the said
bulb. The air pressure in the tube rising from the main reservoir therefore serves
to double purpose of forcing the mercury in the said main reservoir up through the
tube therein and the mercury in the duct between the second bulb and the extension
of the main reservoir and in the valve chamber back against the valve thus firmly
holding and hermetically sealing the said valve in its seat. The mercury flow there-
fore is determined by normal air pressure at one end of the system, and to enable this
to prove effective air is exhausted at the other end of the system.
The mercury continues to flow into the second bulb until its weight above the
valve is sufficient to press it open when the mercury runs back into the main reservoir.
This takes place long before the mercury level in downward extension of the reservoir
can possibly fall below the bottom of the tube therein so that under no circumstance
can air find its way in this manner into the second bulb. The air that is exhausted is
withdrawn from the second bulb.
It will be apparent that the flow of mercury through the fall tubes is continuous
and not intermittent. The mercury from the main reservoir is raised and traverses
the system until its weight above the valve over-balances the upward pressure of the
mercury below the said valve and hence is sufficient to cause this valve to open. The
valve opens for an instant and some of the mercury goes back to the reservoir. The
normal condition of the valve is that of equilibrium, slightly disturbed at intervals,
but as this disturbance has no effect on the constant vacuum maintained in the system
unless it be for the movement to make that vacuum more perfect owing to the descent
by gravity of the mercury from the second bulb it follows that there is no check in
the mercury flow.

page_text: COMPLETE SPECIFICATION.
Improvements in Mercurial Air Pumps.
1, JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex,
Gentleman do hereby declare the nature of this Invention which has been com-
municated to me from abroad by Henry J. Doerr of Newark, Essex County, New
Jersey and Theodore Mace, of 182 Fulton Street New York, both in the United States
of America, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
This Invention relates to improvements in mercurial air-pumps of the Sprengel
type, wherein air is exhausted by the descent of mercury in a vertical tube or
tubes and has for its object to effect a continuous and steady flow of the mercury
whereby one mercury elevating apparatus will suffice for the operation of several sets
of mercury tubes, and whereby the parts of the device can be easily separated for
cleansing or other purpose.
In the accompanying drawings Figure 1 is an elevation and partial section of a
pump constructed according to this invention. Figure 2 is a vertical section of
the upper mercury reservoir. Figure 3 is a vertical section of the mercury jet
discharge tube and Figure 4 shows the mercury elevating apparatus in combina-
tion with several sets of fall tubes.
Like letters of reference indicate corresponding parts in all the figures.
A is the main mercury reservoir having a downward extension B. From the
reservoir A rises a tube A¹ on the upper end of which is a bulb or reservoir D.
In the opening in the top of the reservoir D, and in the tube A¹ just below the
reservoir D are air tight plugs E F. Passing through the plug E is the tube C
which is closed at its upper extremity but near the said extremity there is a
delivery orifice as shown. The tube C extends nearly to the bottom of the downward
extension B of the reservoir A, and is open. From the lower portion of the
reservoir D, a pipe G, leads to the vessel H in the upper part of which there is an
air tight stopper I through which passes a tube J, the open lower end of which is
near the bottom of the vessel H. The vessel H thus forms an air-trap, to prevent
any air in the mercury from being carried into the fall tubes. The tube J passes
into a chamber K in which it is hermetically sealed. In the side of the said tube .J
are several openings I. Extending between the lower portion of the chamber K
and the upper portion of a similar chamber M is a series of fall tubes a a¹ all of
which there may be any desired number. The chamber M communicates by a pipe N
with the upper portion of a bulb O at the lower part of which is a passage P
communicating with the valve chamber Q in which is a valve R provided with
projections S on its lower side, so that it can close the opening between the passage P
and the chamber Q, but not the opening from the chamber Q to the pipe T, which
latter communicates as shown with the extension B of the reservoir A.
Opening into the upper part of the chamber O is a short pipe U communicating

page_text: with another valve chamber V in which is a valve W provided with projec-
tions X on its upper side. The said valve can close the opening from the chamber V
to the passage U but cannot close the opening from the chamber V to the pipe Y
which pipe communicates with the tube A¹ by the connecting tube Z.
From the upper part of the chamber K the exhaust tube communicates with
chamber in which phosphoric anhydride or any other suitable material for drying
the air exhausted from the bulbs or vessels to be exhausted may be placed. The
chamber c communicates by pipes d d with the pipe e to which are connected the
pipes to to which the lamp bulbs g to g (or other vessels to be exhausted) are
secured.
C
The chamber M is provided with stoppers
the fall tubes a a¹ a¹¹."
1111
through which pass the ends of
By removing the said fall tubes from the said stoppers and the tube J from the
stopper I the apparatus can be taken apart for cleansing or other purpose,
The operation of the apparatus is as follows:-
A vacuum pump (which may be of any ordinary construction) is applied to the
tube which enters the reservoir D through the upper stopper F. A pump pro-
ducing alternately vacuum and plenum (which pump may also be of any ordinary
construction) is applied to the end of tube Y. Suppose that the last mentioned pump
first forces air into the tube Y. The valve W will then be forced down and her-
metically closed upon its scat and the air will pass by the pipe Z into the tube A' and
pressing on the mercury will force the said mercury up through the tube Cand into the
reservoir D. This upward flow of the mercury will be assisted by the vacuum caused
in the reservoir D by the pump which constantly draws out air through the tube i.
Meanwhile the pressure on the mercury column in the reservoir A, extension B,
pipe T, and valve chamber Q forces the valve R tightly to its seat. From the
reservoir D the mercury passes by the pipe G through the air seal H, to the tube J,
thence it falls through the fall tubes a a¹ a¹¹.
In this way as is well known, air may be entrained by the descending mercury, and
drawn out of the lamp bulbs or other vessels through the pipe b. The mercury and
entrained air then pass into the chamber M and thence by the pipe N to the
bulb O.
On the exhaust stroke of the pump connected with the tube Y the valve W lifts
and the air in the bulb O is drawn out through the said tube Y.
At the same time air is exhausted through the tube Z from the tube A' above the
mercury in the reservoir A.
There is also the constant vacuum maintained in the tube C. The vacuum pro-
duced in the bulb O obviously draws the mercury through the system and into the
said bulb. Now the mercury which has traversed the system has been taken from
reservoir A, and hence the mercury level will have fallen in the said reservoir. The
noment therefore, that the vacuum is produced above the mercury in the reservoir A
the weight of the mercury which has entered the bulb O pushes down and opens
the valve R, when the mercury from the bulb O flows into the valve chamber Q and
so back by the pipe T to the reservoir A.
Then
Referring now to Figure 4 the invention is here illustrated as arranged with several
sets of fall tubes. The tubes G and N are extended as shown. With the tube G the
air seals H H H communicate by branch tubes G G G and with the tube N the
chambers M M M communicate by the branch pipes N N N The mercury
from the reservoir D passes along the tube G and is distributed to the three sets of
fall tubes 1, 2, 3, through the air seals H H H" and chambers K K' K".
from the chambers M M M the mercury passes by the tubes N N N to the
tube N, and thence to the bulb 0, as already explained. By this construction three
sets of lamps or vessels can be exhausted simultaneously by the aid of a single mercury
elevating device, as shown on the left of Figure 4, thus greatly augmenting the
economy of construction, as well as the capacity of the apparatus. It will be evident
that two or more than three sets of lamps or vessels can be similarly simultaneously
exhausted.

page_text: This
According to a modified construction air pressure is employed at or below normal to
elevate the mercury to the top of the fall tubes and a vacuum is produced in a
reservoir into which the mercury passes after its descent through the said tubes.
The said reservoir is arranged above the reservoir from which the mercury is
originally drawn and a duct is provided leading downwardly from the former to the
latter. In this duct a valve is placed opening downwardly and so arranged as to
support the entire weight of the mercury column in the receiving reservoir.
valve operates automatically to allow the mercury to escape from the said receiving
reservoir into the main mercury reservoir, whenever the weight of the mercury above
the valve exceeds the upward pressure of the mercury in the duct below the valve.
In this way a constant circulation of mercury through the system is maintained, by the
agency of a single mechanical air pump which operates to exhaust air from a suction
tube leading from the mercury in the main reservoir, and also from a branch tube
leading to the receiving reservoir. The air pressure above the mercury in the main
reservoir remains constant at atmospheric pressure, or by closing the air inlet, this
pressure may be reduced, owing to the expansion of the air in the then closed tube,
so that a regulation may thus be secured to achieve the best working results. The air
pressure above the mercury is not increased by any additional device, nor is the same
intermittently altered.
Figure 5 is an elevation of this modification of the improved air pump.
As in the former arrangement A is the mercury reservoir having a downward
extension B. From the reservoir A rises a tube A' on the upper end of which is a
bulb or reservoir D. In the opening in the top of reservoir D'and in the said tube A¹,
just below the said reservoir are air-tight plugs E, F. Passing through the plug E
is the tube . At its upper extremity the tube C is closed, but near the said extremity
it has a delivery orifice as before. The tube C extends nearly to the bottom of the
downward extension B of the reservoir A and is open as hereinbefore described under
the first arrangement.
Y is a tube to which may be connected any ordinary form of air pump. One
branch of the tube Y passes through the plug F into the reservoir D. The other
branch communicates with a bulb which communicates by a duct T with the
extension B of the reservoir A. In the duct is a valve chamber Q containing a
valve R provided with projections S on its lower side, so that while it can close the
upper opening in its chamber it cannot close the lower opening therein. From the
lower portion of the reservoir D a pipe G leads to the vessel H in the upper part of
which is a stopper I through which passes a tube J the open lower end of which
is near the bottom of the vessel H which thus forins as herein before described
an air trap to prevent any air in the mercury from being carried into the fall tubes.
The tube J leads into chamber K in which it is hermetically sealed. In the side of
said tube J within the chamber K are openings L.
Extending between the lower portion of the chamber K and the upper portion
of a similar chamber M is a series of fall tubes a, a. The chamber M communi-
cates by a pipe N with the upper portion of the bulb O. From the upper part of the
chamber a pipe b leads to a chamber c in which phosphoric anhydride or other
drying agent is placed. The chamber c communicates by the pipes d'e and ƒ ƒ ƒ
with the lamp bulbs or vessels from which air is to be exhausted which are attached
to the pipes f
11
Communicating with the tube A' is a pipe A³ which may open into the atmosphere
and may be provided with a stop cock A*.
The operation of this apparatus is as follows:-
A quantity of mercury is placed in the reservoir A. This is prevented from
flowing into the bulb O by the automatic closing of the valve R. The stop cock A
in the pipe A is now opened and a mechanical air pump is applied to the pipe Y
by which means air is exhausted through the tubes Y² and Y₁ from the reservoir D
and also from the bulb O. The production of a partial vacuum in the reservoir D
and the pressure of air admitted through the pipe A³ into the tube A¹ above the
mercury, causes the mercury to rise through the tube C and escape at the orifice

page_text: therein into the reservoir D from which the mercury flows through the pipe G and
vessel H and escapes by the pipe J into the chamber K from which it falls through
the fall tubes a and enters the chamber M. and thence by the pipe N it passes to the
bulb O. From the bulb O it flows finally past the valve R and through the pipe T
back to the reservoir A.
The mercury descending through the fall tubes a entrains with it the air therein
and exhausts air from the tube b drying chamber c and lamp bulbs or vessels f, fll fill
in the manner well understood. The exhaustion mechanically caused at the pipe Y
produces a partial vacuum both in the reservoir D and in the entire system through
the pipe Y bulb O pipe N chamber M, tubes a, chamber K, vessel H, pipe G and so
back to the reservoir D. The air pressure in the tube A¹ therefore serves the double
purpose of forcing the mercury in the reservoir A up through the tube C and the
mercury in the pipe T and chamber Q back against the valve R thus hermetically
closing the said valve to its seat above. The mercury flow therefore is determined
by normal air pressure at one end of the system (air admitted through the pipe A³
pressing on the mercury in the roservoir A) and to enable this to prove effective
air is exhausted at the other end of the system through the pipe Y from the
bulb O.
The mercury continues to flow into the bulb O until its weight above the valve R
is sufficient to press that valve open, when the mercury runs back into the reservoir A.
This takes place long before the mercury level in the tube A¹ can possibly fall below
the bottom of the tube Y so that under no circumstances can air find its way in
this manner into the bulb O. The air that is exhausted from the lamp bulbs or
vessels is withdrawn from the bulb O through the tube Y². It will be apparent that
the flow of mercury through the fall tubes is continuous and not intermittent. The
mercury from the reservoir A is raised and traverses the system until its weight
above the valve R over balances the upward pressure of the mercury below the said
valve and hence is sufficient to cause the said valve to open. The valve opens in an
instant and some of the mercury goes back to the reservoir A. The normal condition
of the valve R is that of equilibrium slightly disturbed at intervals but as this
disturbance has no effect on the constant vacuum maintained in the system unless it
be for the moment to make that vacuum more perfect owing to the descent by
gravity of the mercury from the bulb O it follows that there is no check in the
mercury flow.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
1. In mercurial air pumps the combination of the mercury reservoir A, tube A¹
closed at its upper extremity, upper mercury reservoir D, suction pipe C, extending
between the reservoirs A and D, tube Y, bulb 0, communicating with the said tube Y,
a valve seated in the communication with the tube Y above the bulb O and opening
upwardly a pipe T communicating with the bulb O and the lower portion of the
mercury reservoir A, a valve seated in the communication with the pipe T below
the bulb O and opening downwardly, a connecting pipe Z between the tube Y and
the tube A', a mercury-delivery tube J communicating with the reservoir D, a
chamber K, fall tube a, chamber M, pipe N, leading from the chamber M to the
bulb O, and an exhaust pipe leading from the chamber K substantially as herein-
before described.
2. The arrangement and combination of parts constituting the mercurial air
pump hereinbefore described and illustrated in Figures 1, 2 and 3 of the accompanying
Drawings.
3. The combination of the arrangements hereinbefore described and claimed with
two or more sets of fall tubes and adjuncts so that more than one set of lamps or
vessels can be exhausted by means of a single mercurial elevating device substan-
tially as herein before described and illustrated in Figure 4 of the accompanying
drawings.

page_text: 4. In mercurial air pumps wherein air is exhausted by the descent of a mercury
jet in a tube, a mercury reservoir, a means, such as a suction tube, for elevating the
mercury from said reservoir to the upper portion of the said fall tube or tubes a
vacuum chamber receiving the mercury from the said fall tube or tubes and situated
at a higher elevation than the said mercury reservoir, a duct between the said chamber
and said reservoir, and a downwardly opening valve arranged in the said duct and
supporting the entire weight of the mercury column in the said chamber: the
said valve operating automatically to open and so to allow mercury to pass from the
said chamber to the said reservoir when the downward pressure of the mercury
column in the said chamber above said valve exceeds the upward pressure thereon of
the mercury contained in the duct beneath said valve all substantially as hereinbefore
described.
5. The combination of the mercury reservoir A, upwardly extending tube A¹, plug E
therein, air tube A³, reservoir D, tube C extending between reservoirs D and A,
tube G, closed vessel H, delivery pipe J, chamber K, exhaust pipe b entering the said
chamber, chamber M, a series of vertical fall tubes a extending between the chambers K
and M, bulb O, pipe N between the bulb O and chamber M, duct T, valve chamber Q
in the said duct, valve R and suction tubes Y' and Y2 communicating respectively
with the bulb O and reservoir D substantially as hereinbefore described and illustrated
in Figure 5 of the accompanying drawings.
6. The arrangement and combination of parts constituting the mercurial air
pump substantially as hereinbefore described and illustrated in Figure 5 of the
acccompanying drawings.