Cream shortening and sugar together, adding sugar slowly. Beat in eggs, pumpkin and water. Set aside. Sift together flour, baking powder, salt, ground cloves, allspice, cinnamon and baking soda. Add to pumpkin mixture and stur well. Stir in nuts. Pour batter into greased canning jars, filling half-full. Place jars on cookie sheet. Bake upright in preheated 325 degree oven for about 45 minutes. (Cake will rise and pull away from sides of jar.) When done, remove one jar at a time from oven. While still warm, place wax paper circle on the top end of the cake. Wipe sealing edge of jar. Place lid on jar and close tightly with ring. Turn jar upside down. (Cake will loosen at this time.) Repeat with other jars. Leave jars upside down until sealed. (Jar is sealed if lid remains flat when pressed in center.) To serve: Open jar, slide a knife around inside of the jar to loosen the cake, and remove the cake from the jar. Warm cake in the oven if desired. Slice and serve with whipped cream. This dessert treat is baked and presented in a wide-mouth canning jar. Because the jar is sealed, the cake keeps indefinitely. It can be made ahead of the holidays.