diff --git a/resis/ResReadExt.c b/resis/ResReadExt.c
index 9ee11ef2..5e96db81 100644
--- a/resis/ResReadExt.c
+++ b/resis/ResReadExt.c
@@ -800,9 +800,11 @@ ResReadDevice(int argc,
      * be simpler if all devices just put "None" in this position.
      */
     n = argc - i;
-    if ((n % 3) == 1)	/* Device has a substrate argument */
+    if ((n % 3) == 1)
     {
-	if (strcmp(argv[i], "None"))
+	/* Device has a substrate argument or a numerical value */
+
+	if (strcmp(argv[i], "None") && (!StrIsNumeric(argv[i])))
 	{
 	    entry = HashFind(&ResNodeTable, argv[i]);
 	    device->subs = (ResExtNode *)HashGetValue(entry);
diff --git a/resis/ResRex.c b/resis/ResRex.c
index 6d7756c4..bd1a1cc8 100644
--- a/resis/ResRex.c
+++ b/resis/ResRex.c
@@ -350,7 +350,7 @@ typedef enum {
 	    if (cmd->tx_argc > 2)
 	    {
 		resisdata->minres = MagAtof(cmd->tx_argv[2]);
-		if (resisdata->minres <= 0)
+		if (resisdata->minres < 0)
 		{
 		    TxError("Usage:  %s minres [value]\n", cmd->tx_argv[0]);
 			return;