These are the order: 
1. Sheep Droppings 
2. Pig's ear 
3. Snow 
4. Brandy 
5. Dishwater 
 
 
The total volume of the second and third ingredients was less than half of the cauldron volume. 
means... 
The 1st 2nd and 3rd has to be: 
Snow(1/4) 
Pig's ears(1/5) 
Sheep Droppings(1/6) 
because... 
(1/4 + 1/5 + 1/6) 1 
 
Tadaaaaa! 
O_o

Actually... 
my first answer was particularly for.. 
The total volume of the first,second and third less than 1/2! 
But 
The total volume of the second and third ingredients was less than half of the cauldron volume 
doesnt say anything about the first... 
So,  
We have 4 possible pair of ingredients for 2nd and 3rd: 
(1/3 + 1/6) 
(1/4 + 1/5) 
(1/4 + 1/6) 
(1/5 + 1/6) 
 
out of those... 
I still get another correct answer that satisfies everything in the question:  
1. Pig's ear 
2. Brandy 
3. Sheep droppings 
4. Dishwater 
5. Snow  
 

hahahahahahahaa....! 
I was just kidding... :P 
 
I have the CORRECT answer now. 
 
We have 4 possible pair of ingredients for 2nd and 3rd: 
(1/3 + 1/6) 
(1/4 + 1/5) 
(1/4 + 1/6) 
(1/5 + 1/6) 
 
FOR(1/3 + 1/6): 
1. Pig's ear 
2. Brandy 
3. Sheep droppings 
4. Dishwater 
5. Snow  
But 
1/5 + 1/3 + 1/6 + 1/2 
=> 0.20 +0.33 +0.166+ 0.5 > 1 
So, the cauldron is already full. There's no room for Snow. 
The order is not correct. 
 
Another possible order: 
FOR(1/4 + 1/5) 
1. Sheep droppings 
2. Pig's ear 
3. Snow 
4. Brandy 
5. Dishwater 
This is actually the correct order since: 
1/6 +1/5 +1/4 +1/3 ~ 0.96  
5. Dishwater 
 
Gotcha!!... 
why u tricky lil....! u 
 
O_O