the preferred embodiments of the present invention will now be described with reference to fig1 - 16 of the drawings . identical elements in the various figures are designated with the same reference numerals . fig1 shows a projectile 10 having an ogive 12 , a mortar body 14 and a vent 16 in a mortar tail 18 . the projectile 10 is equipped with a tubular vessel 20 having five separate compartments , a , b , c , d and e , arranged in sequence with compartment a closest to the tail . as shown in fig2 , the compartments in the tubular vessel 20 are separated by membranes or seals 22 , 23 , 24 and 25 , respectively . the seal 22 , which separates compartments a and b , and the seal 24 , which separates compartments c and d are designed to withstand the forces on setback ( launch ) of the projectile . seals 23 and 25 , on the other hand , are designed to break upon setback , allowing the components in compartments b and c , on one hand , and d and e , on the other , to mix on setback . thus , upon setback , the acceleration forces , and also possibly centrifugal forces , cause the components of compartments b - c and d - e to mix . when fitted to an airdrop bomb , use is made of wind and / or air pressure to activate devices which break seals 23 and 25 , so that , in this case also , the components in compartments b - c and d - e mix . the compartments a , b , c , d and e contain the following components : a : a carrier containing red dye powder for daytime marking of the point of impact . b and c : two components of chemi - luminescent materials which , when mixed , glow brightly . d and e : two components which , when mixed , create a gas pressure , and / or two components which , when mixed , create heat . the literature is replete with examples of chemi - luminescent materials . see , for example , u . s . pat . no . 5 , 348 , 690 . examples of chemical components which , when mixed , create heat ( called exothermic reactions ) include ( 1 ) powdered metals with water , for example the iron catalyzed reaction of magnesium powder with water , used to heat mres ( meals ready for eating ), ( 2 ) powdered metal oxides with water , for example calcium oxide ( quicklime ) with water , ( 3 ) powdered metals with aqueous metal salt solutions , for example zinc powder with copper sulfate solution , ( 4 ) hydration of anhydrous salts , for example water and anhydrous calcium chloride or copper sulfate , and ( 5 ) polymerization reactions , for example the catalyzed polymerization of mono - methacrylate . examples of chemical components which , when mixed , create pressure ( gas generating reactions ) include ( 1 ) powdered metals with water or dilute acids , for example zinc powder and hydrochloric acid , ( 2 ) calcium carbide with water , ( 3 ) powdered metal carbonates or bicarbonates with dilute acids , for example calcium carbonate and citric acid . to achieve quick mixing and rapid reaction of the chemicals , it is desirable to use liquid components or a mixture of liquid and powdered solid components . it is best to avoid combustion reactions in the projectile , because of the risk of causing fires and to keep the projectile free from energetic materials , thus avoiding eod issues . fig3 is a detailed view of the projectile showing the five compartment tubular vessel 20 fitted into the mortar body 14 , an ogive 12 including a piston , and a venting configuration 16 in the tail of the mortar . on setback , as shown in fig4 , the membranes between compartments b - c and d - e break allowing their components to mix in flight . as indicated in fig5 , when the components in compartments b and c mix , they form a chemi - luminescent mixture which begins to glow . when the components of compartments d and e mix , they react and produce either a gas under pressure and / or heat . during flight , as depicted in fig6 , the chemi - luminescent mixture increases in brightness until it reaches its maximum luminescent output at the end of the projectiles trajectory . as indicated in fig7 , the reactants from the compartments d and e pressurize the tubular vessel 20 during flight . alternatively or in addition , the temperature within the tubular vessel rises during the trajectory , warming the chemi - luminescent materials so that they glow , notwithstanding extreme low ambient temperatures . this is illustrated in fig8 . in fig9 , immediately prior to impact , the chemi - luminescent materials reach their peak luminence and the reactants in compartments d and e near their peak pressure . if the projectile were to impact against a solid surface , the mortar body would burst and the dry powder mix and the chemi - luminescent liquid would be dispersed . however , especially in the case of a projectile which impacts with a high angle - of - attack , the projectile may land on soft soil and not burst open , with a result that marking of the point of impact would not ordinarily occur . the present invention provides a remedy for this situation since , during flight , a chemical reaction pressurizes the vessel 20 within the mortar body during flight , to cause the marking materials to disperse . the projectile may also include a piston 26 connected to the ogive 12 . upon striking the ground , the piston depresses , further pressurizing the vessel and leading to a failure of a seal 28 that covers the vent 16 at the rear of the mortar body . without pressurization of the vessel or the provision of the piston , the device would not work in all cases where heavy projectiles ( traveling at high velocity ) may penetrate too deeply into the ground , thereby precluding effective expulsion of the marking material . see estimating ordnance penetration into earth by crul , taylor and tipton , us army engineering and support center , huntsville ala . this paper describes the correlation of actual recovery data and hydracode runs to provide a understanding of the depth that various projectiles will penetrate the earth after impact . fig1 shows the projectile at the commencement of impact with the ground . when this occurs , the piston 26 compresses , further pressurizing the vessel and resulting in failure of the rear seal 28 . after this rear seal fails , the pressure venting leads to the ejection of an expendable “ carrier ” or slug 30 filled with dry marker material , such as a red dye powder . after expulsion from the vessel , the carrier releases the dry powder plume . also , due to the pressure in the vessel 20 , a column of mixed chemi - luminescent liquid 32 is ejected through the vent . the expulsion of the chemi - luminescent material may utilize laminar flow technology to maximize the height ( head ) of the ejected material . fig1 - 15 depict the sequence of projectile function upon compression of the piston . the dry marker carrier 30 is followed by the chemi - luminescent mix 32 . with a heavy projectile traveling at high velocity , it may be necessary to eject marking material using well known pyrotechnic devices . such devices will still utilize a stacked configuration ejecting ( with one charge ) both the dry marker 30 and the chemi - luminescent materials 32 . fig1 and 15 show how the dry marker powder material 30 , which expands to form a plume , and the chemi - luminescent liquid material are ejected from the vent 16 and expand to mark the point of impact , both by day ( plume 30 ) and night ( glowing liquid 32 ). in conclusion , the marking device of the present invention provides for efficient ejection of dry mix and heated chemi - luminescent liquid so that the location of impact is marked with a multi - spectral visual , infra - red and thermal signature . the marking device is initiated at setback and is operative during the flight of the projectile to cause both day and night marker materials to be ejected from the projectile upon impact . the marking device according to the invention is intended to operate at any ambient temperature and with any type of impact , be it hard or soft , to mark the point of impact . while embodiments of the present invention have been illustrated and described , it will be clear that the present invention is not limited to these embodiments only . numerous modifications , changes , variations , substitutions and equivalents will be apparent to those skilled in the art , without departing from the spirit and scope of the present invention , as described in the claims .