diff --git a/game_api.txt b/game_api.txt
index 8123c0109ba194b52990d7caeb3acfe229191f4e..6ce69f09f46cb796508b60b8a29af525b4d77ba9 100644
--- a/game_api.txt
+++ b/game_api.txt
@@ -83,7 +83,7 @@ farming.register_plant(name, Plant definition)
 	steps = 8,	-- How many steps the plant has to grow, until it can be harvested
 	^ Always provide a plant texture for ech step, format: modname_plantname_i.png (i = stepnumber)
 	minlight = 13, -- Minimum light to grow
-	maxlight = LIGHT_MAX -- Maximum light to grow
+	maxlight = default.LIGHT_MAX -- Maximum light to grow
 }
 
 Stairs API
@@ -148,6 +148,11 @@ default.node_sound_wood_defaults()
 default.node_sound_leaves_defaults()
 default.node_sound_glass_defaults()
 
+Default constants
+-----------------
+default.LIGHT_MAX
+^ The maximum light level (see [Node definition] light_source)
+
 Player API
 ----------
 The player API can register player models and update the player's appearence
diff --git a/mods/default/init.lua b/mods/default/init.lua
index 276af54391e885d58bfc416d2487333263009242..663a3ae12c5dbc5809d4ea36185184dfaa528e06 100644
--- a/mods/default/init.lua
+++ b/mods/default/init.lua
@@ -1,16 +1,13 @@
 -- Minetest 0.4 mod: default
 -- See README.txt for licensing and other information.
 
--- The API documentation in here was moved into doc/lua_api.txt
-
-WATER_ALPHA = 160
-WATER_VISC = 1
-LAVA_VISC = 7
-LIGHT_MAX = 14
+-- The API documentation in here was moved into game_api.txt
 
 -- Definitions made by this mod that other mods can use too
 default = {}
 
+default.LIGHT_MAX = 14
+
 -- GUI related stuff
 default.gui_bg = "bgcolor[#080808BB;true]"
 default.gui_bg_img = "background[5,5;1,1;gui_formbg.png;true]"
@@ -46,3 +43,9 @@ dofile(minetest.get_modpath("default").."/mapgen.lua")
 dofile(minetest.get_modpath("default").."/player.lua")
 dofile(minetest.get_modpath("default").."/trees.lua")
 dofile(minetest.get_modpath("default").."/aliases.lua")
+
+-- Legacy:
+WATER_ALPHA = minetest.registered_nodes["default:water_source"].alpha
+WATER_VISC = minetest.registered_nodes["default:water_source"].liquid_viscosity
+LAVA_VISC = minetest.registered_nodes["default:lava_source"].liquid_viscosity
+LIGHT_MAX = default.LIGHT_MAX
diff --git a/mods/default/nodes.lua b/mods/default/nodes.lua
index 90b6dbd7d1539d81bb2424083df1b95886aea219..fcc34bbfd1a7b03a61efb8c2a66138d3cf758b92 100644
--- a/mods/default/nodes.lua
+++ b/mods/default/nodes.lua
@@ -547,7 +547,7 @@ minetest.register_node("default:water_flowing", {
 			animation={type="vertical_frames", aspect_w=16, aspect_h=16, length=0.8}
 		},
 	},
-	alpha = WATER_ALPHA,
+	alpha = 160,
 	paramtype = "light",
 	paramtype2 = "flowingliquid",
 	walkable = false,
@@ -559,7 +559,7 @@ minetest.register_node("default:water_flowing", {
 	liquidtype = "flowing",
 	liquid_alternative_flowing = "default:water_flowing",
 	liquid_alternative_source = "default:water_source",
-	liquid_viscosity = WATER_VISC,
+	liquid_viscosity = 1,
 	post_effect_color = {a=64, r=100, g=100, b=200},
 	groups = {water=3, liquid=3, puts_out_fire=1, not_in_creative_inventory=1},
 })
@@ -579,7 +579,7 @@ minetest.register_node("default:water_source", {
 			backface_culling = false,
 		}
 	},
-	alpha = WATER_ALPHA,
+	alpha = 160,
 	paramtype = "light",
 	walkable = false,
 	pointable = false,
@@ -590,7 +590,7 @@ minetest.register_node("default:water_source", {
 	liquidtype = "source",
 	liquid_alternative_flowing = "default:water_flowing",
 	liquid_alternative_source = "default:water_source",
-	liquid_viscosity = WATER_VISC,
+	liquid_viscosity = 1,
 	post_effect_color = {a=64, r=100, g=100, b=200},
 	groups = {water=3, liquid=3, puts_out_fire=1},
 })
@@ -614,7 +614,7 @@ minetest.register_node("default:lava_flowing", {
 	},
 	paramtype = "light",
 	paramtype2 = "flowingliquid",
-	light_source = LIGHT_MAX - 1,
+	light_source = default.LIGHT_MAX - 1,
 	walkable = false,
 	pointable = false,
 	diggable = false,
@@ -624,7 +624,7 @@ minetest.register_node("default:lava_flowing", {
 	liquidtype = "flowing",
 	liquid_alternative_flowing = "default:lava_flowing",
 	liquid_alternative_source = "default:lava_source",
-	liquid_viscosity = LAVA_VISC,
+	liquid_viscosity = 7,
 	liquid_renewable = false,
 	damage_per_second = 4*2,
 	post_effect_color = {a=192, r=255, g=64, b=0},
@@ -647,7 +647,7 @@ minetest.register_node("default:lava_source", {
 		}
 	},
 	paramtype = "light",
-	light_source = LIGHT_MAX - 1,
+	light_source = default.LIGHT_MAX - 1,
 	walkable = false,
 	pointable = false,
 	diggable = false,
@@ -657,7 +657,7 @@ minetest.register_node("default:lava_source", {
 	liquidtype = "source",
 	liquid_alternative_flowing = "default:lava_flowing",
 	liquid_alternative_source = "default:lava_source",
-	liquid_viscosity = LAVA_VISC,
+	liquid_viscosity = 7,
 	liquid_renewable = false,
 	damage_per_second = 4*2,
 	post_effect_color = {a=192, r=255, g=64, b=0},
@@ -680,7 +680,7 @@ minetest.register_node("default:torch", {
 	sunlight_propagates = true,
 	is_ground_content = false,
 	walkable = false,
-	light_source = LIGHT_MAX-1,
+	light_source = default.LIGHT_MAX - 1,
 	selection_box = {
 		type = "wallmounted",
 		wall_top = {-0.1, 0.5-0.6, -0.1, 0.1, 0.5, 0.1},
diff --git a/mods/farming/API.txt b/mods/farming/API.txt
index a2f3d9d611e6518193e4dcb47e2dbad62344ccab..9234bc44364940fcfc73ff552303473eecdf36a7 100644
--- a/mods/farming/API.txt
+++ b/mods/farming/API.txt
@@ -23,5 +23,5 @@ Plant definition
 	steps = 8,	-- How many steps the plant has to grow, until it can be harvested
 	^ Always provide a plant texture for ech step, format: modname_plantname_i.png (i = stepnumber)
 	minlight = 13, -- Minimum light to grow
-	maxlight = LIGHT_MAX -- Maximum light to grow
+	maxlight = default.LIGHT_MAX -- Maximum light to grow
 }
\ No newline at end of file
diff --git a/mods/farming/init.lua b/mods/farming/init.lua
index 9245470fdba2f4b889ce254c45fdbb3761a4a45a..d3157a073c7f7747b41deaa5a07953d768e7d4b3 100644
--- a/mods/farming/init.lua
+++ b/mods/farming/init.lua
@@ -13,7 +13,7 @@ farming.register_plant("farming:wheat", {
 	inventory_image = "farming_wheat_seed.png",
 	steps = 8,
 	minlight = 13,
-	maxlight = LIGHT_MAX,
+	maxlight = default.LIGHT_MAX,
 	fertility = {"grassland"}
 })
 minetest.register_craftitem("farming:flour", {
@@ -46,7 +46,7 @@ farming.register_plant("farming:cotton", {
 	inventory_image = "farming_cotton_seed.png",
 	steps = 8,
 	minlight = 13,
-	maxlight = LIGHT_MAX,
+	maxlight = default.LIGHT_MAX,
 	fertility = {"grassland", "desert"}
 })
 
diff --git a/mods/tnt/init.lua b/mods/tnt/init.lua
index a2e5adaa87b3a435316134f91f4ccbfeee0bc826..fda4ec399dc5d15524ce6684a3b53890675f165f 100644
--- a/mods/tnt/init.lua
+++ b/mods/tnt/init.lua
@@ -255,7 +255,7 @@ minetest.register_node("tnt:tnt_burning", {
 minetest.register_node("tnt:boom", {
 	drawtype = "plantlike",
 	tiles = {"tnt_boom.png"},
-	light_source = LIGHT_MAX,
+	light_source = default.LIGHT_MAX,
 	walkable = false,
 	drop = "",
 	groups = {dig_immediate=3},